3-Alkyl-5- (4-alkyl-5-oxo-tetrahydrofutran-2-yl) pyrrolidin-2-one Derivatives as Intermediates in the Synthesis of Renin Inhibitors

ABSTRACT

The invention related to a novel process, novel process steps and novel intermediates useful in the synthesis of pharmaceutically active compounds, especially renin inhibitors, such as Aliskiren. Inter alia, the invention relates to a process for the manufacture of a compound of the formula II, 
     
       
         
         
             
             
         
       
     
     or a salt thereof, and a compound of formula VI 
     
       
         
         
             
             
         
       
     
     or a salt thereof, wherein R 3  and R 4  as well as Act are as defined in the specification, and processes of manufacturing these. 
     Additionally transformation of compounds (VI) with metallo organic compounds (VII) give rise to the new compounds (VIII) which are direct precursors for the preparation of Aliskiren.

FIELD OF THE INVENTION

The present invention relates to novel C-8 lactam lactone compounds.Moreover, the present invention provides methods for preparing these C-8lactam lactone compounds.

These C-8 lactam lactone compounds are more specifically5-(5-oxo-tetrahydro-furan-2-yl)pyrrolidin-2-one compounds according toformula (II) as shown below. Such compounds are key intermediates in thepreparation of renin inhibitors, in particular2(S),4(S),5(S),7(S)-2,7-dialkyl-4-hydroxy-5-amino-8-aryl-octanoyl amidederivatives, or pharmaceutically acceptable salts thereof. Therefore,present invention is also directed to useful intermediates in thepreparation of these renin inhibitors as well as methods for preparingthese renin inhibitors and its intermediates.

BACKGROUND OF THE INVENTION

Renin passes from the kidneys into the blood where it affects thecleavage of angiotensinogen, releasing the decapeptide angiotensin Iwhich is then cleaved in the lungs, the kidneys and other organs to formthe octapeptide angiotensin II. The octapeptide increases blood pressureboth directly by arterial vasoconstriction and indirectly by liberatingfrom the adrenal glands the sodium-ion-retaining hormone aldosterone,accompanied by an increase in extracellular fluid volume which increasecan be attributed to the action of angiotensin II. Inhibitors of theenzymatic activity of renin lead to a reduction in the formation ofangiotensin I, and consequently a smaller amount of angiotensin II isproduced. The reduced concentration of that active peptide hormone is adirect cause of the hypotensive effect of renin inhibitors.

With compounds such as (with INN name) aliskiren((2S,4S,5S,7S)-5-amino-N-(2-carbamoyl-2-methylpropyl)-4-hydroxy-2-isopropyl-7-[4-methoxy-3-(3-methoxypropoxy)benzyl]-8-methylnonanamide),a new antihypertensive has been developed which interferes with therenin-angiotensin system at the beginning of angiotensin IIbiosynthesis.

As the compound comprises 4 chiral carbon atoms, the synthesis of theenantiomerically pure compound is quite demanding. Therefore, amendedroutes of synthesis that allow for more convenient synthesis of thissophisticated type of molecules are welcome.

Such 2(S),4(S),5(S),7(S)-2,7-dialkyl-4-hydroxy-5-amino-8-aryl-octanoylamide derivatives are any of those having renin inhibitory activity and,therefore, pharmaceutical utility and include, e.g., those disclosed inU.S. Pat. No. 5,559,111. So far, various methods of preparing2(S),4(S),5(S),7(S)-2,7-dialkyl-4-hydroxy-5-amino-8-aryl-octanoyl amidederivatives are described in the literature.

In EP-A-0678 503, δ-amino-γ-hydroxy-ω-aryl-alkanecarboxamides aredescribed, which exhibit renin-inhibiting properties and could be usedas antihypertensive agents in pharmaceutical preparations.

In WO 02/02508, a multistep manufacturing process to obtainδ-amino-γ-hydroxy-ω-aryl-alkanecarboxamides is described, in which thecentral intermediate is a 2,7-dialkyl-8-aryl-4-octenic acid or a2,7-dialkyl-8-aryl-4-octenic acid ester. The double bond of thisintermediate is simultaneously halogenated in the 4/5 position andhydroxylated in the 4-position via (under) halo-lactonisationconditions. The halolactone is converted to a hydroxy lactone and thenthe hydroxy group is converted to a leaving group, the leaving group issubstituted with azide, the lactone amidated and then the azide isconverted into the amine group.

Further processes for the preparation of intermediates to manufactureδ-amino-γ-hydroxy-ω-aryl-alkanecarboxamides are described in WO02/092828pertaining to the preparation of 2-alkyl-5-halogenpent-4-ene carboxylicesters, WO 2001/009079 pertaining to the preparation of2-alkyl-5-halogenpent-4-ene carboxylic acids, WO 02/08172 pertaining tothe preparation of 2,7-dialkyl-4-hydroxy-5-amino-8-aryloctanoyl amides,WO 02/02500 pertaining to 2-alkyl-3-phenylpropionic acids, andWO02/024878 pertaining to 2-alkyl-3-phenylpropanols.

In EP-A-1215201 an alternative route to obtainδ-amino-γ-hydroxy-ω-aryl-alkanecarboxamides is disclosed. InGB-A-0511686.8 yet an alternative route to obtainδ-amino-γ-hydroxy-ω-aryl-alkanecarboxamides is disclosed using apyrrolidine intermediate.

Although the existing processes may lead to the desired renininhibitors, in particular the2(S),4(S),5(S),7(S)-2,7-dialkyl-4-hydroxy-5-amino-8-aryl-octanoyl amidederivatives, there exists a need to provide an alternative syntheticroute to these2(S),4(S),5(S),7(S)-2,7-dialkyl-4-hydroxy-5-amino-8-aryl-octanoyl amidederivatives to ensure its manufacture in a simple and efficient manner.

SUMMARY OF THE INVENTION

Surprisingly, it has now been found that renin inhibitors, in particular2(S),4(S),5(S),7(S)-2,7-dialkyl-4-hydroxy-5-amino-8-aryl-octanoyl amidederivatives, are obtainable in high diastereomeric and enantiomericpurity and in an economic manner using a novel C-8 lactam lactonecompound, in particular, a5-(5-oxo-tetrahydro-furan-2-yl)pyrrolidin-2-one compound, as thestarting material. In particular it was found that by using a C-8 lactamlactone compound, in particular, a5-(5-oxo-tetrahydro-furan-2-yl)pyrrolidin-2-one compound as a chiralbuilding block and introducing the organic aromatic moiety at the end ofthe synthesis, the process is more economic than the prior art processeswhere the organic aromatic moiety is introduced to the scaffold in earlystep of the synthesis sequences. Moreover, utilizing a C-8 lactamlactone compound conveniently locks and preserves the stereochemistryand, thus, simplifies the method of preparing such sophisticated typesof molecules.

DETAILED DESCRIPTION OF THE INVENTION

Therefore in a first aspect, the present invention relates to a compoundof the formula (II)

whereinR³ is C₁₋₇alkyl or C₃₋₈cycloalkyl; andR⁴ is C₁₋₇alkyl, C₂₋₇alkenyl, C₃₋₈cycloalkyl, phenyl- ornaphthyl-C₁₋₄alkyl each unsubstituted or mono-, di- or tri-substitutedby C₁₋₄alkyl, O—C₁₋₄alkyl, OH, C₁₋₄alkylamino, di-C₁₋₄alkylamino,halogen and/or by trifluoromethyl; or a salt thereof.

In a preferred embodiment, R³ is C₁₋₇alkyl, preferably branchedC₃₋₆alkyl, most preferably isopropyl.

In a preferred embodiment, R⁴ is C₁₋₇alkyl, preferably branchedC₃₋₆alkyl, most preferably isopropyl.

Preferably, the compound according to the formula (II) has the followingstereochemistry:

Most preferably, the compound of formula (II) has the followingstructure:

A compound of the formula (II) may be used, inter alia, for thesynthesis of pharmaceutically active substances, preferably renininhibitors such as aliskiren, especially as described in the following.

The present inventors have found convenient methods of preparing the keyintermediate of the formula (II) as will be described in detail below.Any of the reaction steps either alone or in a suitable combination maybe employed to yield the compound of the formula (II). Moreover, any ofthe following reaction steps either alone or in a suitable combinationmay be employed in the synthesis of a renin inhibitor, such asaliskiren.

Thus, in one aspect, the present invention relates to a method forpreparing a compound of formula (II) as described above, said processcomprising subjecting a compound of formula (I)

wherein R³ and R⁴ are as defined for a compound of formula (II), or asalt thereof, to hydrogenation to convert the azide moiety to an amineand to effect lactam ring closure. This process step as such, also formsan embodiment of the invention.

Preferred embodiments for R³ and R⁴ can be taken from the definitionsfor compounds of formula (II). Preferably, the compound according to theformula (I) has the following stereochemistry:

Compounds of the formula (I) can be obtained by methods well known inthe art, in particular by following the procedures for preparingcompound III in EP-A-0 678 514 which is incorporated herein byreference, in particular as disclosed in the working examples,especially example 2, in particular using conversion 2.c1.

Alternatively, a compound of formula (II) can be prepared using adifferent auxiliary than the one employed in the compound of formula(I).

Thus, in one aspect, the present invention relates to a method forpreparing a compound of formula (II) as described above, said processcomprising subjecting a compound of formula (I′)

wherein R³ and R⁴ are as defined for a compound of formula (II) and Aux*is an auxiliary able to form an ester or amide with the carbonylfunctionality, or a salt thereof, to hydrogenation to convert the azidemoiety to an amine and to effect lactam ring closure. This process stepas such, also forms an embodiment of the invention.

Preferred examples of Aux* include ephedrine compounds, oxazolidinoneanalogues, methylpyrrolidone analogues, carbohydrate analogues, andcyclic alcohols or amines. Typical examples include those describedbelow as well as analogues thereof, in particular oxazolidone analogues,such as the Evans auxiliary or in more general terms chiralα-substituted oxazolidinone analogues. The literature for preparingthese auxiliaries is mentioned below for further detail. Apart from theEvans auxiliary used in the compound of formula (I), ephedrine typeauxiliaries and cyclic alcohol type auxiliaries such as (+)-fenchol, arepreferred.

The compound of formula (I′) can be prepared by following theexperimental procedure as outlined in EP-A-0 678 514 for the Evansauxiliary. Thus, a suitable acid chloride represented by formula (I′i)such as 3-methyl-butyryl chloride

wherein R³ is as defined for a compound of formula (II), or a saltthereof, is reacted with the respective Aux*-H, wherein Aux* is asdefined for a compound of formula (I′) in the presence of a suitablebase to obtain a compound of formula (I′ii)

Similarly, the reaction can be conducted with an acid chloride of theformula (I′iii)

wherein R⁴ is as defined for a compound of formula (II), or a saltthereof, and the respective Aux*-H, wherein Aux* is as defined for acompound of formula (I′) in the presence of a suitable base to obtain acompound of formula (I′iv)

The compounds of formula (I′ii) and (I′iv) are in turn reacted with(E)-1,4-Dibromo-but-2-ene of the formula (I′v)

in the presence of a strong base to yield a compound of the formula(I′vi)

wherein R³ and R⁴ are as defined for a compound of formula (II) and Aux*is as defined for a compound of formula (I′), or a salt thereof.

If R³ and R⁴ are identical, i.e. R³=R⁴, it is appreciated that 2 or moreequivalents of a compound of formula (I′ii) are reacted with(E)-1,4-Dibromo-but-2-ene of the formula (I′v).

Thus a compound of the formula (I′vi)

whereinR³ is C₁₋₇alkyl or C₃₋₈cycloalkyl;R⁴ is C₁₋₇alkyl, C₂₋₇alkenyl, C₃₋₈cycloalkyl, phenyl- ornaphthyl-C₁₋₄alkyl each unsubstituted or mono-, di- or tri-substitutedby C₁₋₄alkyl, O—C₁₋₄alkyl, OH, C₁₋₄alkylamino, di-C₁₋₄alkylamino,halogen and/or by trifluoromethyl; and

Aux* is an auxiliary able to form an ester or amide with the carbonylfunctionality; or a salt thereof,

is a valuable intermediate of the process of preparing renin inhibitorssuch as aliskiren, in an efficient manner. Therefore such compounds aswell as the method of obtaining compound (II) using this intermediate(I′vi) also form an embodiment of the invention.

The compound of formula (I′vi) is further reacted with a halogenationagent such as NCS, NBS, NIS (all N-halosuccinimides), Br₂ orbromohydantoin, using halolactonization reaction conditions to form acompound of formula (I′vii)

wherein R³ and R⁴ are as defined for a compound of formula (II), Aux* isas defined for a compound of formula (I′) and Hal is a halogen, or asalt thereof.

The halogen functionality of the compound of formula (I′vii) is thenconverted into an azide by inversion using a N₃ ⁻ source to obtain thecompound of formula (I′). Examples of the N₃ ⁻ source include standardreagents such as LiN₃, NaN₃, KN₃, MeN₃, alkyl ammonium azides of thetype (alkyl)₄NN₃ or alkyl)₃NHN₃ or e.g. tetraalkylguanidinium azides ororganometalic azides. The reaction proceeds under conditions well knownin the art such as in a homogeneous or biphasic solvent mixture or inionic liquids or mixtures of an ionic liquid. Preferably, the reactiontakes place at temperatures in the range of 0 to 120° C., such as 20 to100° C., preferable 50 to 80° C.

The reaction to convert the azide moiety of the compound of formula (I)or (I′) to an amine and to effect lactam ring closure preferably takesplace under conditions so as to keep the other functionalities on themolecule intact. Hydrogenation typically takes place in the presence ofa catalyst selected from a heterogeneous catalyst or a homogeneouscatalyst, such as Wilkinson's catalyst, preferably a heterogeneouscatalyst. Examples of the catalyst include Raney nickel, palladium/C,Pd(OH)₂ (Perlman's catalyst), nickel boride, platinum metal or platinummetal oxide, rhodium, ruthenium and zinc oxide, more preferablypalladium/C, platinum metal or platinum metal oxide, most preferablypalladium/C. The catalyst is preferably used in an amount of 1 to 20%,more preferably 5 to 10%. The reaction can be conducted at atmosphericor elevated pressure, such as a pressure of 2-10 bar, e.g. 5 bar, morepreferably the reaction is conducted at atmospheric pressure. Thehydrogenation takes place preferably in an inert solvent, morepreferably in tetrahydrofuran or toluene. Also suitable are proticsolvents, such as alcohol, e.g. ethanol or methanol, or ethyl acetate.These solvents may be used in the presence of water. The reaction timeand the temperature are chosen so as to bring the reaction to completionat a minimum time without the production of unwanted side products.Typically the reaction can be conducted at 0° C. to reflux, preferably 0to 60° C., such as 0 to 40° C., more preferably 15-30° C., such as roomtemperature, for 10 min to 12 h, preferably 20 min to 6 h, mostpreferably 30 min to 4 h, such as 1 to 3 h or 6 to 12 h.

During the hydrogenation of compound (I) or (I′) stoichiometric amountsof the protonated auxiliary Aux*-H, such as the oxazolidinone, namelythe chiral auxiliary (e.g. (S)-Evans reagent) are split off. Becauseboth compounds (II) and the auxiliary, such as the Evans auxiliary, areboth crystalline and have similar properties, it is preferred toseparate both compounds and at the same time recycle the expensiveauxiliary by a simple separation technique (crystallization orextraction). It was found that by saponification of the lactone ring ofthe lactam lactone (II) a transfer into the aqueous phase is possibledue to lactone ring opening whereas the oxazolidinone (or the auxiliaryin general) stays in the organic phase. By simple phase separationfollowed by acidification of the water phase a re-lactonisation ispossible, which allows the isolation of pure compound (II).Saponification is preferably achieved by treatment with bases likeorganic or inorganic bases, preferably inorganic bases. Examples includeLiOH or NaOH. The saponification is typically conducted in a suitablesolvent. Examples include aqueous systems or aqueous/organic solventmixtures and even organic solvents such as alcohols or toluene, wherebyalcohol/water mixtures, such as ethanolic/aqueous solutions, arepreferred. After phase separation, the aqueous phase is typicallyacidified to protonate the γ-hydroxy acid salt and to obtain theγ-hydroxy acid in the free form. Typical acids suitable for theacidification are chosen so that they are stronger than the γ-hydroxyacid but keep the other functionalities on the molecule intact. Suitableacids include organic acids, such as citric acid, tartaric acid orsimilar acids, or dilute inorganic acids such as dilute HCl. The freeacid will re-form the lactone (II), preferably by heating the mixture toe.g. 30 to 80° C., more preferably 40 to 60° C., such as 50° C.

Thus a compound of the formula (II′)

whereinR³ is C₁₋₇alkyl or C₃₋₈cycloalkyl; andR⁴ is C₁₋₇alkyl, C₂₋₇alkenyl, C₃₋₈cycloalkyl, phenyl- ornaphthyl-C₁₋₄alkyl each unsubstituted or mono-, di- or tri-substitutedby C₁₋₄alkyl, O—C₁₋₄alkyl, OH, C₁₋₄alkylamino, di-C₁₋₄alkylamino,halogen and/or by trifluoromethyl; or a salt thereof,is a valuable intermediate of the process of preparing renin inhibitorssuch as aliskiren, in an efficient manner. Therefore such compounds aswell as the method of obtaining compound (II) using this intermediate(II′) also form an embodiment of the invention.

Preferred embodiments of compound (II) are also preferred for compound(II′). In particular the following stereochemistry is preferred:

Preferably, the compound has the following formula

As an alternative approach to obtain the compound of the formula (II),the present invention relates in another aspect to a method forpreparing a compound of formula (II) as defined above, said processcomprising subjecting a compound of formula (III)

wherein R³ and R⁴ are as defined for a compound of formula (II), or asalt thereof, to conversion to an anhydride of formula (IV)

wherein R³ and R⁴ are as defined for a compound of formula (II) and R⁶is C₁₋₇alkyl or C₃₋₈cycloalkyl, or a salt thereof; to activate the acidmoiety followed by hydrogenation to convert the azide moiety to an amineand to effect lactam ring closure. This process step as such as well asthe compound of formula (IV), also forms an embodiment of the invention.

Preferred embodiments for R³ and R⁴ can be taken from the definitionsfor compounds of formula (II).

In a preferred embodiment, R⁶ is C₁₋₇alkyl, more preferably straightchain or branched C₁₋₄ alkyl, most preferably methyl, ethyl, isopropylor isobutyl.

Preferably, the compound according to the formula (IV) has the followingstereochemistry:

Compounds of the formula (III) can be obtained by methods well known inthe art, in particular from compounds of the formula (I) as definedabove by following the procedures for preparing such compounds in EP-A-0678 514 which is incorporated herein by reference, in particular asdisclosed in the working examples, especially example 3. Analogously,compounds of formula (I′) can be converted to compounds of formula (II)following these procedures.

Both conversions may be conducted as separate steps by isolating theanhydride of the formula (IV) or by conducting them as a one-potsynthesis without isolation. Preferably the reaction mixture obtainedafter the formation of the anhydride of the formula (IV) is directlysubjected to hydrogenation.

The reaction of the compound of the formula (III) to form the mixedanhydride of formula (IV) to activate the acid moiety preferably takesplace under conditions so as to keep the other functionalities on themolecule intact. The anhydride is typically introduced using anactivated acid, such as an acid chloride R⁶—CO—Cl. It is preferred toadd the activated acid over a certain period of time. Preferably thereaction is conducted under basic or acidic conditions, more preferablybasic conditions. Suitable bases include organic or inorganic bases,preferably organic bases, more preferably a nitrogen base, yet morepreferably a tertiary nitrogen base. Examples of the tertiary nitrogenbase include trimethylamine, DBU, triethylamine anddiisopropylethylamine. The reaction can be conducted in any suitablesolvent, preferably an aprotic solvent such as ether, in particular THFand TBME, an aromatic or a halogenated solvent, more preferably THF ortoluene. The reaction time and the temperature are chosen so as to bringthe reaction to completion at a minimum time without the production ofunwanted side products. Typically the reaction can be conducted at −20°C. to reflux, preferably −10 to 40° C., more preferably 0-30° C., such 0to 10° C., for 1 min to 12 h, preferably 10 min h to 4 h, mostpreferably 15 min to 2 h, such as 30 min to 1 h.

Reference is made to standard procedures well known to the person in theart and as described e.g. in Houben-Weyl, Vol. E5/2 (1985), p. 934-1183,Houben-Weyl, Vol. E5/1 (1985), p. 193-773, and Houben-Weyl, Vol. 8(1952), p. 359-680, which are incorporated herein by reference.

The reaction of the compound of the formula (IV) to convert the azidemoiety to an amine and to effect lactam ring closure preferably takesplace under conditions so as to keep the other functionalities on themolecule intact. Hydrogenation typically takes place in the presence ofa catalyst selected from a heterogeneous catalyst or a homogeneouscatalyst, such as Wilkinson's catalyst, preferably a heterogeneouscatalyst. Examples of the catalyst include Raney nickel, palladium/C,Pd(OH)₂ (Perlman's catalyst), nickel boride, platinum metal or platinummetal oxide, rhodium, ruthenium and zinc oxide, more preferablypalladium/C, platinum metal or platinum metal oxide, most preferablypalladium/C. The catalyst is preferably used in an amount of 1 to 20%,more preferably 5 to 10%. The reaction can be conducted at atmosphericor elevated pressure, such as a pressure of 2-10 bar, e.g. 5 bar, morepreferably the reaction is conducted at atmospheric pressure. Thehydrogenation takes place preferably in an inert solvent, morepreferably in tetrahydrofuran or toluene. The reaction time and thetemperature are chosen so as to bring the reaction to completion at aminimum time without the production of unwanted side products. Typicallythe reaction can be conducted at 0° C. to reflux, preferably 0 to 40°C., more preferably 15-30° C., such as room temperature, for 30 min to48 h, preferably 2 h to 36 h, most preferably 12 min to 24 h, such as 17to 23 h.

As yet an alternative approach to obtain the compound of the formula(II), the present invention relates in another aspect to a method forpreparing a compound of formula (II) as defined above, said processcomprising subjecting a compound of formula (III)

wherein R³ and R⁴ are as defined for a compound of formula (II), or asalt thereof, to conversion to an ester of formula (V)

wherein R³ and R⁴ are as defined for a compound of formula (II) and R⁷is C₁₋₇alkyl or C₃₋₈cycloalkyl, or a salt thereof; followed byhydrogenation to convert the azide moiety to an amine and to effectlactam ring closure. This process step as such as well as the compoundof formula (V) also forms an embodiment of the invention.

Preferred embodiments for R³ and R⁴ can be taken from the definitionsfor compounds of formula (II).

In a preferred embodiment, R⁷ is C₁₋₇alkyl, more preferably straightchain or branched C₁₋₄alkyl, most preferably methyl, ethyl, n-propyl,isopropyl, n-butyl, t-butyl or isobutyl.

Preferably, the compound according to the formula (V) has the followingstereochemistry:

Compounds of the formula (III) which are used as starting materials forthis conversion can be obtained as described above.

Both conversions may be conducted as separate steps by isolating theester of the formula (V) or by conducting them as a one-pot synthesiswithout isolation. Preferably the reaction mixture obtained after theformation of the ester of the formula (V) is directly subjected tohydrogenation.

The reaction of the compound of the formula (III) to form the ester offormula (V) preferably takes place under conditions so as to keep theother functionalities on the molecule intact. The ester is typicallyintroduced by converting the acid (III) to an activated acid, such as anacid chloride with a suitable reagent such a SOCl₂. Alternatively, theester can be introduced in a fast and efficient manner by employing asuitable R⁷-triazene as the alkyl donor with the concomitant evolutionof nitrogen. Examples of the triazene include aryl triazenes such as3-methyl-1-(p-tolyl)-triazene. The reaction can be conducted preferablyunder neutral conditions. The reaction can be conducted in any suitablesolvent, preferably an aprotic solvent such as ether, such as THF orTBME, an aromatic or a halogenated solvent, more preferably THF,methylene chloride or toluene. The reaction time and the temperature arechosen so as to bring the reaction to completion at a minimum timewithout the production of unwanted side products. Typically the reactioncan be conducted at 0° C. to reflux, preferably 10 to 40° C., morepreferably 15-30° C., such as room temperature, for 1 min to 12 h,preferably 10 min h to 6 h, most preferably 30 min to 4 h, such as 2 to3 h or until all nitrogen evolution has stopped. Several otherprocedures for making esters from carboxylic acid are described forexample in: Organicum, Wiley-VCH, Ed. 20, (1999) p. 442 which isincorporated herein by reference.

The reaction of the compound of the formula (V) to convert the azidemoiety to an amine and to effect lactam ring closure preferably takesplace under conditions so as to keep the other functionalities on themolecule intact. Hydrogenation typically takes place in the presence ofa catalyst selected from a heterogeneous catalyst or a homogeneouscatalyst, such as Wilkinson's catalyst, preferably a heterogeneouscatalyst. Examples of the catalyst include Raney nickel, palladium/C,Pd(OH)₂ (Perlman's catalyst), nickel boride, platinum metal or platinummetal oxide, rhodium, ruthenium and zinc oxide, more preferablypalladium/C, platinum metal or platinum metal oxide, most preferablypalladium/C. The catalyst is preferably used in an amount of 1 to 20%,more preferably 5 to 10%. The reaction can be conducted at atmosphericor elevated pressure, such as a pressure of 2-10 bar, e.g. 5 bar, morepreferably the reaction is conducted at atmospheric pressure. Thehydrogenation takes place preferably in an inert solvent, morepreferably in tetrahydrofuran or toluene. The reaction time and thetemperature are chosen so as to bring the reaction to completion at aminimum time without the production of unwanted side products. Typicallythe reaction can be conducted at 0° C. to reflux, preferably 0 to 40°C., more preferably 15-30° C., such as room temperature, for 30 min to48 h, preferably 2 h to 36 h, most preferably 12 to 24 h, such as 17 to23 h.

The different approaches to obtain the compound of formula (II) aresummarized below in Scheme 1:

Scheme 1 exemplifies as the auxiliary the Evans auxiliary but otherauxiliaries as outlined for compound (I′) are also possible. Thus, thesame routes to the C-8 lactam lactone of formula (II) as shown in Scheme1 apply by using the compound of formula (I′) as the starting material.

In a preferred further embodiment of the invention, this synthesiscomprises as a further step or as an individual synthesis thepreparation of a compound of formula (VI)

wherein R³ and R⁴ are as defined for a compound of formula (II) and Actis an activating group selected from an amino protecting group, inparticular a carbamate, or a salt thereof; comprising introducing theactivating group at the nitrogen of a compound of formula (II), or asalt thereof. This process step as such as well as compounds of formula(VI) also form embodiments of the invention.

This conversion proceeds under standard conditions and as described e.g.in standard reference works, such as J. F. W. McOmie, “Protective Groupsin Organic Chemistry”, Plenum Press, London and New York 1973, in T. W.Greene and P. G. M. Wuts, “Protective Groups in Organic Synthesis”,Third edition, Wiley, New York 1999, in “The Peptides”; Volume 3(editors: E. Gross and J. Meienhofer), Academic Press, London and NewYork 1981, in “Methoden der organischen Chemie” (Methods of OrganicChemistry), Houben Weyl, 4th edition, Volume 15/I, Georg Thieme Verlag,Stuttgart 1974, in H.-D. Jakubke and H. Jeschkeit, “Aminosäuren,Peptide, Proteine” (Amino acids, Peptides, Proteins), Verlag Chemie,Weinheim, Deerfield Beach, and Basel 1982, and in Jochen Lehmann,“Chemie der Kohlenhydrate: Monosaccharide and Derivate” (Chemistry ofCarbohydrates: Monosaccharides and Derivatives), Georg Thieme Verlag,Stuttgart 1974 which are incorporated herein by reference.

In particular when Act is an alkoxy carbonyl group so as to form acarbamate, the reaction is preferably conducted under basic conditions.The base can be used stoichiometrically or catalytically. Suitable basesinclude organic or inorganic bases, preferably organic bases, morepreferably a nitrogen base, yet more preferably a tertiary nitrogenbase. Examples of the tertiary nitrogen base include triethylamine,diisopropylethylamine, DBU, TMEDA and trimethylamine. DMAP can be usedas a catalyst. The reaction can be conducted in any suitable solvent,preferably a polar solvent such as an ethyl acetate or isopropylacetate, an ether, such as THF or TBME, or a halogenated solvent, morepreferably THF, methylene chloride or isopropyl acetate. The reactiontime and the temperature are chosen so as to bring the reaction tocompletion at a minimum time without the production of unwanted sideproducts. Typically the reaction can be conducted at 0° C. to reflux,preferably 0 to 60° C., more preferably 15-50° C., such as 20-45° C.,for 10 min to 36 h, preferably 3 h to 24 h, most preferably 6 h to 24 h,such as 12-17 h.

Another important embodiment of the invention relates to a compound ofthe formula (VI)

whereinR³ is C₁₋₇alkyl or C₃₋₈cycloalkyl;R⁴ is C₁₋₇alkyl, C₂₋₇alkenyl, C₃₋₈cycloalkyl, phenyl- ornaphthyl-C₁₋₄alkyl each unsubstituted or mono-, di- or tri-substitutedby C₁₋₄alkyl, O—C₁₋₄alkyl, OH, C₁₋₄alkylamino, di-C₁₋₄alkylamino,halogen and/or by trifluoromethyl; and

Act is an activating group selected from an amino protecting group, inparticular a carbamate; or a salt thereof. In another preferredembodiment, Act is an acyl or a substituted sulfonyl group.

In a preferred embodiment, R³ is C₁₋₇alkyl, preferably branchedC₃₋₆alkyl, most preferably isopropyl.

In a preferred embodiment, R⁴ is C₁₋₇alkyl, preferably branchedC₃₋₆alkyl, most preferably isopropyl.

In a preferred embodiment, Act is an N-protecting group, for example, anamino protecting group which is conventionally used in peptide chemistry(cf.: “Protective groups in Organic Synthesis”, 5^(th). Ed. T. W. Greene& P. G. M. Wuts, which is incorporated herein by reference), especiallyin the chemistry of protecting pyrrolidines. In the following theterminology “Act” is maintained throughout the synthesis sequence forsake of consistency. It is appreciated that “Act” serves as anactivating group when present on the lactam nitrogen and that afterlactam opening the Act group is a protecting group.

Preferred protecting groups comprise, for example, (i) C₁-C₂-alkyl thatis mono-, di- or trisubstituted by phenyl, such as benzyl, (or)benzhydryl or trityl, wherein the phenyl ring is unsubstituted orsubstituted by one or more, e.g. two or three, residues e.g. thoseselected from the group consisting of C₁-C₇alkyl, hydroxy,C_(r)C₇alkoxy, C₂-C₈-alkanoyl-oxy, halogen, nitro, cyano, and CF₃;phenyl-C₁-C₂-alkoxycarbonyl; and allyl or cinnamyl. Especially preferredare benzyloxycarbonyl (Cbz), 9-fluorenylmethyloxycarbony (Fmoc),benzyloxymethyl (BOM), pivaloyl-oxy-methyl (POM),trichloroethxoycarbonyl (Troc), 1-adamantyloxycarbonxyl (Adoc), but canalso be benzyl, cumyl, benzhydryl, trityl, allyl, C₁₋₁₀ alkenyloxycarbonyl, such as alloc (allyloxycarbonyl). The protecting group canalso be silyl, like trialklysilyl, especially trimethylsilyl,tert.-butyl-dimethylsilyl, triethylsilyl, triisopropylsilyl,trimethylsilyethoxymethyl (SEM), and can also be substituted sulfonyl(e.g. C₁-C₇alkyl, aryl such as phenyl, substituted aryl such as withC₁-C₇alkyl, halo, hydroxyl or C₁-C₇alkoxy substituted phenyl, inparticular tosyl (4-methyl-phenyl sulfonyl), or camphorsulfonyl) orsubstituted sulfenyl (subst. arylsulfenyl). For the use of sulfonyl andacyl groups it is referred to D. Savoia, et al., J. Org. Chem., 54, 228(1989), and literature cited there.

Examples for Act include C₁₋₁₀alkenyloxy carbonyl, C₆₋₁₀aryl-C₁₋₆alkyl,and C₁₋₆alkyl-carbonyl, C₆₋₁₀aryl-carbonyl, C₁₋₆alkoxy-carbonyl,C₆₋₁₀aryl-C₁₋₆alkoxycarbonyl, C₁₋₆alkyl-sulfonyl, or C₆₋₁₀aryl-sulfonyl,such as C₁₋₁₀ alkenyloxy carbonyl, C₆₋₁₀aryl-C₁₋₆alkyl, andC₁₋₆alkyl-carbonyl, C₆₋₁₀aryl-carbonyl, C₁₋₆alkoxy-carbonyl, andC₆₋₁₀aryl-C₁₋₆alkoxycarbonyl. In a preferred embodiment, Act isC₆₋₁₀aryl-C₁₋₆alkoxycarbonyl, C₁₋₆alkoxy-carbonyl, allyloxycarbonyl orC₆₋₁₀aryl-C₁₋₆alkyl such as benzyl, t-butoxycarbonyl orbenzyloxycarbonyl. In a preferred embodiment, Act is t-butoxy- orbenzyloxycarbonyl.

Preferably, the compound according to the formula (VI) has the followingstereochemistry:

More preferably, the compound of formula (VI) has the followingstructure:

Most preferably, the compound of formula (VI) has the followingstructure:

A compound of the formula (VI) may be used, inter alia, for thesynthesis of pharmaceutically active substances, preferably renininhibitors such as aliskiren, especially as described in the following.

In a preferred further embodiment of the invention, this synthesiscomprises as a further step or as an individual synthesis thepreparation a compound of formula (VIII)

wherein R³ and R⁴ are as defined for a compound of formula (II) and Actis an activating group selected from an amino protecting group, inparticular a carbamate, R¹ is halogen, hydroxyl, C₁₋₆halogenalkyl,C₁₋₆alkoxy-C₁₋₆alkyloxy or C₁₋₆alkoxy-C₁₋₆alkyl; R² is halogen,hydroxyl, C₁₋₄alkyl or C₁₋₄alkoxy, or a salt thereof;comprising the step of lactam ring opening of the N-activated lactamlactone of formula (VI) or a salt thereof defined above with a compoundof formula (VII)

wherein Y is a metal containing group such as —Li, —MgX, -magnesates,aryl magnesium species such as

wherein R1 and R2 are as defined herein,alkyl magnesium species, such as branched C₁₋₇alkyl-Mg—, —MnX,(alkyl)₃MnLi—, or —CeX₂, wherein X is halogen such as Cl, I or Br, morepreferably Br; and R¹ and R² are as defined for a compound of formula(VIII) above. This process step as such as well as the compounds (VIII)and (VII) also form embodiments of the invention. For this conversion,see also D. Savoia, et al., J. Org. Chem., 54, 228 (1989), andliterature cited there.

Preferred embodiments for R³, R⁴ and Act for compound of formula (VIII)can be taken from the definitions for compounds of formula (VI).

In a preferred embodiment, R¹ is hydroxyl, C₁₋₆alkoxy-C₁₋₆alkyloxy orC₁₋₆alkoxy-C₁₋₆alkyl, more preferably C₁₋₄alkoxy-C₁₋₄alkyloxy, mostpreferably methoxypropoxy.

In a preferred embodiment, R² is hydroxyl or C₁₋₄alkoxy, more preferablybranched C₁₋₄alkoxy, most preferably methoxy.

Preferably, the compound according to the formula (VIII) has thefollowing stereochemistry:

Preferred examples the compound according to the formula (VIII) have thefollowing formula:

Compounds of formula (VII) are obtainable from compounds of formula(VII′), preferably in situ:

wherein X is halogen such as Cl, I or Br, more preferably Br; and R¹ andR² are as defined for a compound of formula (VIII) above.

Compounds of formula (VII) can be prepared according to methods wellknown to the person skilled in the art, in particular halogen metalexchange procedures, e.g. as described in the following literaturereferences describing several different approaches:

Lit. 1: for magnesates: a) K. Oshima et al., Angew. Chem., Int. Ed.2000, 39, 2481 and lit. cited therein. b) K. Oshima et al.; J.Organomet. Chem., 1999, 575, 1-20. c) K. Oshima et al., J. Org. Chem.,66, 4333 (2001); d) A. Akao et al., Tetrahedron Lett., 47, 1877 (2006);

-   e) K. Ishihara et al., Org. Lett., 7, 573 (2005), reports addition    of trialkyl MgLi-magnesates to carbonyl groups; f) T. Mase et al.,    Tetrahedron Lett., 42, 4841 (2001).    Lit. 2: for Grignard reagents:-   a) P. Knochel et al., Angew. Chem. Int. Ed 2000, 39, 4414-   b) P. Knochel et al., Angew. Chem. Int. Ed. 2003, 42, 4438-   c) Houben-Weyl, Vol. 13/2a, page 53-526-   d) P. Knochel et al.; Synthesis 2002, 565,-   e) P. Knochel et al., Angew. Chem., 118, 165 (2006), electron rich    diaryl Mg compounds-   f) S. Hall et al., Heterocycles, 24, 1205 (1987), direct Li-halogen    exchange with Li metal-   g) Pat. Appl.; DE 10240262 A1, 2004, 3 Nov., direct Li-halogen    exchange with Li metal-   h) C. Feugeas, Bull. Soc. Chim. Fr., (8) 1892-1895 (1964); direct    action of Mg metal to electron rich bromo aryl compounds to give    electron rich Mg compounds-   i) C. Feugeas, Comptes Rendus, 90, (1), 113-116 (1965); direct    action of Mg metal to electron rich bromo aryl compounds-   j) B. Bogdanovic et al., Angew. Chem., Int. Ed., 39, 4610 (2000)-   k) Handbook of Grignard Reagents (Eds. G. S. Silverman, P. E.    Rakita) Marcel Dekker, New York, 1996-   l) N. Krause, “Metallorganische Chemie”, Spektrum Akademischer    Verlag, Heidelberg, 1996, Chapter 3-   m) “Grignard Reagents—New Developments”, Ed. H. G. Richey, John    Wiley & Sons, Chichester, 2000.    all of which are incorporated herein by reference.

Typically, the organometallic species (VII) is prepared from compound(VII′) according to the different literature mentioned above. Usuallythe reaction takes place in an inert solvent, more preferably intetrahydrofuran, other ethers or toluene, or in solvent mixtures such asmixtures of ethers like THF and alkanes like hexane, heptane orcyclohexane. The reaction time and the temperature are chosen so as tobring the reaction to completion at a minimum time without theproduction of unwanted side products. Typically the reaction can beconducted at low temperatures or at room temperature, such as 0 to 30°C., more preferably 0 to 20° C. In one embodiment, the reaction can beconducted at 0° C. or below, preferably −80 to −20° C., more preferably−80 to −40° C., such as −78 to −50° C., for 30 min h to 10 h, preferably1 h to 5 h, most preferably 1.5 to 4 h, such as 2 to 3 h.

The special challenge in the case of compound (VIII) reacting with ametallo organic species like (VII′) lies in the chemo selectivedifferentiation between reaction at the lactam moiety versus the lactonemoiety. By introducing an activating group Act at the lactam nitrogen,it was found by the present inventors that surprisingly only the lactamring is opened and the lactone stays intact.

Compounds of formula (VII) were found to be important reagents in theabove conversion and, thus, the synthesis of renin inhibitors.Therefore, in one aspect the present invention also relates to acompound of formula (VII)

wherein Y is a metal containing group such as —Li, —MgX, -magnesates,aryl magnesium species such as

wherein R1 and R2 are as defined herein,alkyl magnesium species, such as branched C₁₋₇alkyl-Mg—, —MnX,(alkyl)₃MnLi—, or —CeX₂ wherein X is halogen such as Cl, I or Br, morepreferably Br; R¹ is halogen, hydroxyl, C₁₋₆halogenalkyl,C₁₋₆alkoxy-C₁₋₆alkyloxy or C₁₋₆alkoxy-C₁₋₆alkyl; and R² is halogen,hydroxyl, C₁₋₄alkyl or C₁₋₄alkoxy; or a salt thereof. Such compoundsmake it possible to connect the aromatic moiety of the renin inhibitorto the carbon chain in an efficient manner.

Preferably Y is Li, a magnesate or MgBr, more preferably Li or MgBr,still more preferably MgBr. Preferably the compounds of formula (VII)have the following structures:

In one embodiment, compounds having the following structure arepreferred:

Preferably the compound of formula (VII′) has the following structure:

After the conversion of compound (VI) to compound (VIII) it is preferredto separate compound (VIII) in a simple and convenient manner withoutextensive purification techniques. Similar as in the work-up of compound(II) it was found that by saponification of the lactone ring of thecompound (VIII) a transfer into the aqueous phase is possible due tolactone ring opening whereas possible by-products stay in the organicphase. By simple phase separation followed by acidification of the waterphase a re-lactonisation is possible, which allows the isolation of purecompound (VIII). Saponification is preferably achieved by treatment withbases like organic or inorganic bases, preferably inorganic bases.Examples include LiOH, NaOH, K₂CO₃ or Na₂CO₃, preferably LiOH or NaOH.The saponification is typically conducted in a suitable solvent.Examples include aqueous systems or aqueous/organic solvent mixtures andeven organic solvents such as alcohols or toluene, whereby alcohol/watermixtures, such as ethanolic/aqueous solutions, are preferred. Afterphase separation, the aqueous phase is typically acidified to protonatethe γ-hydroxy acid salt to obtain the γ-hydroxy acid in the free form.Typical acids suitable for the acidification are chosen so that they arestronger than the γ-hydroxy acid but keep the other functionalities onthe molecule, in particular the Act group, intact. Suitable acidsinclude organic acids, such as citric acid, tartaric acid, oxalic acidor similar acids, or dilute inorganic acids such as dilute HCl. The freeacid will re-form the lactone moiety of compound (VIII), preferably byheating the mixture to e.g. 30 to 80° C., more preferably 40 to 60° C.,such as 50° C.

Thus a compound of the formula (VIII′)

whereinR³ is C₁₋₇alkyl or C₃₋₈cycloalkyl;R⁴ is C₁₋₇alkyl, C₂₋₇alkenyl, C₃₋₈cycloalkyl, phenyl- ornaphthyl-C₁₋₄alkyl each unsubstituted or mono-, di- or tri-substitutedby C₁₋₄alkyl, O—C₁₋₄alkyl, OH, C₁₋₄alkylamino, di-C₁₋₄alkylamino,halogen and/or by trifluoromethyl;R¹ is halogen, hydroxyl, C₁₋₆halogenalkyl, C₁₋₆alkoxy-C₁₋₆alkyloxy orC₁₋₆alkoxy-C₁₋₆alkyl;R² is halogen, hydroxyl, C₁₋₄alkyl or C₁₋₄alkoxy; and

Act is an activating group selected from an amino protecting group, inparticular a carbamate; or a salt thereof; is a valuable intermediate ofthe process of preparing renin inhibitors such as aliskiren, in anefficient manner. Therefore such compounds as well as the method ofobtaining compound (VIII) using this intermediate (VIII′) also form anembodiment of the invention.

Particularly preferred examples of the compound of formula (VIII′)include a salt, namely a carboxylate salt. Preferred examples includeinorganic salts such as alkaline and alkaline earth metal salts, such asLi, Na, K, Mg, Ca salts, or organic salts, such as primary, secondary ortertiary amine salts. Examples of primary amines includeC₃₋₈cycloalkylamines such as cyclohexylamine, primary aromatic amines,such as aniline, aryl alkyl amines such as benzylamine and includingaryl branched alkyl amines such as phenyl- or naphthylethylamine.Secondary amines include N di-substituted (C₁₋₇alkyl, C₃₋₈cycloalkyl,phenyl, and/or phenyl-C₁₋₄alkyl)amines such as di(C₁₋₇alkyl)amines ordicyclohexylamine. Tertiary amines include N tri-substituted (C₁₋₇alkyl,C₃₋₈cycloalkyl, phenyl, and/or phenyl-C₁₋₄alkyl)amines. Particularlypreferred is the Li salt.

The advantage of using the compound of formula (VIII) in the form of thesalt is the opportunity to yield a solid, preferably a crystalline,material that is easier to handle in the production process. Anotheradvantage is that a broader range of reducing agents can be employed forthe reduction of the C8 carbonyl group when the C1 carbonyl is a salt ofa carboxylic acid and not part of a lactone.

Such a salt can be obtained by standard procedures known in the art andas described in the examples. As one method, the salt is obtaineddirectly from the saponification after ring opening of the compound offormula (VIII) with the respective base as described above.Alternatively, the free acid of formula (VIII′) can be basified todeprotonate the γ-hydroxy acid salt to obtain the γ-hydroxy acid in thesalt form. Typical bases suitable for the salt formation are chosen sothat they convert the acid to the salt but keep the otherfunctionalities on the molecule, in particular the Act group, intact.Suitable bases include inorganic bases, such as LiOH, NaOH, Ca(OH)₂,K₂CO₃, Na₂CO₃, Mg(OH)₂, MgCO₃, or organic bases such as amine bases, inparticular primary, secondary or tertiary amine bases, in particular theones mentioned above.

Preferred embodiments of compound (VIII) are also preferred for compound(VIII′). In particular the following stereochemistry is preferred:

or preferably a salt thereof, in particular as described herein.Preferably, the compound has the following formula

or preferably a salt thereof, in particular as described herein.

In a preferred further embodiment of the invention, this synthesiscomprises as a further step or as an individual synthesis thepreparation a compound of formula (IX)

wherein R³ and R⁴ are as defined for a compound of formula (II), R¹ andR² are as defined for a compound of formula (VIII) and Act is anactivating group selected from an amino protecting group, in particulara carbamate, or a salt thereof, comprising reduction of the benzyliccarbonyl of the compound of formula (VIII) as defined above to amethylene moiety. This process step as such, also forms an embodiment ofthe invention. Similarly, this reaction can be performed by using thecompound of formula (VIII′) or a salt thereof as the starting material.

Preferred embodiments for R³, R⁴ and Act can be taken from thedefinitions for compounds of formula (VI) and preferred embodiments forR¹ and R² can be taken from the definitions for compounds of formula(VIII). Preferably, the compound according to the formula (IX) has thefollowing stereochemistry:

The reduction to the C8 methylene moiety can be achieved by variousmeans. Typically, hydrogenation and/or reduction with a hydride can beemployed and whenever the term “reduction” is used in general terms inthis application, it embraces both a hydrogenation and a reduction witha hydride. Possible conversions and intermediates are shown in Scheme 2.Each process step as such as well as the respective intermediates alsoform an embodiment of the invention.

The reduction to compound (IX) can proceed either in a single step or intwo steps with the corresponding alcohol (X) as an intermediate

whereinR³ is C₁₋₇alkyl or C₃₋₈cycloalkyl;R⁴ is C₁₋₇alkyl, C₂₋₇alkenyl, C₃₋₈cycloalkyl, phenyl- ornaphthyl-C₁₋₄alkyl each unsubstituted or mono-, di- or tri-substitutedby C₁₋₄alkyl, O—C₁₋₄alkyl, OH, C₁₋₄alkylamino, di-C₁₋₄alkylamino,halogen and/or by trifluoromethyl;R¹ is halogen, hydroxyl, C₁₋₆halogenalkyl, C₁₋₆alkoxy-C₁₋₆alkyloxy orC₁₋₆alkoxy-C₁₋₆alkyl;R² is halogen, hydroxyl, C₁₋₄alkyl or C₁₋₄alkoxy; andAct is an activating group selected from an amino protecting group, inparticular a carbamate; or a salt thereof.

Compounds of formula (X) were found to be important reactants in theabove conversion and, thus, the synthesis of renin inhibitors.Therefore, one aspect of the present invention also is directed tocompounds of formula (X). Preferred embodiments are the same as forcompound (VIII). The alcohol functionality is typically epimeric andboth epimers can be isolated. Preferably, the compound according to theformula (X) has the following stereochemistry:

Most preferably, compounds of formula (X) have the following structure:

When employing the single step method, the reaction also proceeds viathe alcohol (X) which can be isolated. This reaction to convert thecarbonyl moiety to a methylene function in position 8 preferably takesplace under conditions so as to keep the other functionalities on themolecule intact, in particular the group Act. The conversion to themethylene moiety takes place typically by hydrogenation. Hydrogenationtypically takes place in the presence of a catalyst selected from aheterogeneous catalyst or a homogeneous catalyst, such as Wilkinson'scatalyst, but preferably a heterogeneous catalyst. Examples of thecatalyst include Raney nickel, palladium/C, Pd(OH)₂ (Perlman'scatalyst), nickel boride, platinum metal or platinum metal oxide,rhodium complexes, ruthenium complexes and zinc oxide, more preferablypalladium/C, platinum metal or platinum metal oxide, or Raney nickel,most preferably palladium/C. The catalyst is preferably used in anamount of 1 to 20%, more preferably 5 to 10%. The reaction can beconducted at atmospheric or elevated pressure, such as a pressure of2-10 bar, e.g. 5 bar, more preferably the reaction is conducted atelevated pressure. The hydrogenation takes place preferably in an inertsolvent, more preferably in tetrahydrofuran, toluene, methanol, ethanoland also mixtures of this solvents with water are possible. The reactiontime and the temperature are chosen so as to bring the reaction tocompletion at a minimum time without the production of unwanted sideproducts. Typically the reaction can be conducted at 0° C. to reflux,preferably 0 to 100° C., more preferably 15-70° C., such 30-60° C., for60 min to 12 h, such as 2 h to 6 h. Longer reaction times may also beappropriate to ensure complete conversion, such as 8 to 24 h.

Alternatively the carbonyl moiety may be first converted to an alcohol(X) by reduction with a complex hydride and then subjected to furtherreduction (hydrogenolysis) to obtain a compound of formula (IX).

The reduction to an alcohol preferably takes place under conditions soas to keep the other functionalities on the molecule intact, inparticular the Act group and the lactone moiety. ee Lit.: M.Larcheveque, et al., J. C. S. Chem. Commun., 83 (1985). Such a reactionis well known to a person skilled in the art and is described e.g. inMethoden der organischen Chemie” (Methods of Organic Chemistry), HoubenWeyl, 4th edition, Volume IV/c, Reduction I & II. Georg Thieme Verlag,Stuttgart 1974, pp. 1-486 all of which are incorporated herein byreference.

a) R. L. Augustine, “Reduktion”, Marcel Dekker, Inc., New York, 1968,1-94, b) F. Zymalkowski, “Katalytische Hydrierungen”, Ferdinand EnkeVerlag, Stuttgart, 1965, pp. 103-114, 121-125, 126-144

c) O. H. Wheeler, in “Chemistry of the carbonyl group”, Ed. S. Patai,Interscience, New York, 1966, Chapt. 11.

d) R. H. Mitchell et al., Tetrahedron Lett., 21, 2637 (1980); e) R. T.Blickenstaff et al., Tetrahedron, 24, 2495 (1968);

The reduction typically takes place in the presence of a suitablereducing agent selected from L-Selectride, lithium trialkoxyaluminiumhydrides, for example, lithium tri-tert-butyloxy aluminium hydride,lithium triethylborohydride (Super Hydride®), lithium tri-sec. butylborohydride) or lithium tri n-butyl borohydride (Lit.: A.-M. Faucher etal., Tetrahedr. Let., 39, 8425 (1998), and M. Larcheveque et al., J. C.S. Chem. Commun., 83 (1985)), or lithium tri-tert.-butoxy aluminiumhydride, tetraalkyl-ammoniumborohydrides, Zn(BH₄)₂ and NaBH₄ or byaddition of a Lewis acid like CeCl₃ to the NaBH₄. The reduction takesplace preferably in an inert solvent, more preferably intetrahydrofuran, dichloromethane or toluene or in mixtures of thissolvents or in THF/water or ethanol/water (in the case of water solublesubstrates with NaBH₄ or tetraalkylammonium borohxdride). Lit.: Fieser &Fieser, Vol. XII, page 441, and other volumes. The reaction time and thetemperature are chosen so as to bring the reaction to completion at aminimum time without the production of unwanted side products. Typicallythe reaction can be conducted at 0° C. to reflux, preferably 10 to 100°C., more preferably 20 to 80° C., such as 30-60° C., for 1 to 48 h,preferably 2 h to 12 h, most preferably 3 h to 6 h.

As the next step, the alcohol (X) is further reduced to a compound offormula (IX). This conversion to the methylene moiety takes placetypically by hydrogenation. Hydrogenation typically takes place in thepresence of a catalyst selected from a heterogeneous catalyst or ahomogeneous catalyst, such as Wilkinson's catalyst, preferably aheterogeneous catalyst. Examples of the catalyst include Raney nickel,palladium/C, Pd(OH)₂ (Perlman's catalyst), nickel boride, platinum metalor platinum metal oxide, rhodium, ruthenium and zinc oxide, morepreferably palladium/C, platinum metal or platinum metal oxide, mostpreferably palladium/C. The catalyst is preferably used in an amount of1 to 20%, more preferably 5 to 10%. The reaction can be conducted atatmospheric or elevated pressure, such as a pressure of 2-10 bar, e.g. 5bar, more preferably the reaction is conducted at elevated pressure. Thehydrogenation takes place preferably in an inert solvent, morepreferably in tetrahydrofuran, ethyl acetate, toluene, methanol,ethanol, isopropanol and also mixtures of this solvents with water arepossible. The reaction time and the temperature are chosen so as tobring the reaction to completion at a minimum time without theproduction of unwanted side products. Typically the reaction can beconducted at 0° C. to reflux, preferably 0 to 100° C., more preferably15-70° C., such 30-60° C., for 6 h to 48 h, preferably 10 h to 36 h,most preferably 12 h to 24 h, such as 20-24 h.

The reduction to compound (IX) can also proceed with the correspondingcompound (VIII′) as a starting material as described above, inparticular in the form of a salt such as a Li salt. Preferredembodiments are as described above. In a similar manner as disclosedabove, this reaction may proceed in a single step or via thecorresponding alcohol (X′) as an intermediate

whereinR³ is C₁₋₇alkyl or C₃₋₈cycloalkyl;R⁴ is C₁₋₇alkyl, C₂₋₇alkenyl, C₃₋₈cycloalkyl, phenyl- ornaphthyl-C₁₋₄alkyl each unsubstituted or mono-, di- or tri-substitutedby C₁₋₄alkyl, O—C₁₋₄alkyl, OH, C₁₋₄alkylamino, di-C₁₋₄alkylamino,halogen and/or by trifluoromethyl;R¹ is halogen, hydroxyl, C₁₋₆halogenalkyl, C₁₋₆alkoxy-C₁₋₆alkyloxy orC₁₋₆alkoxy-C₁₋₆alkyl;R² is halogen, hydroxyl, C₁₋₄alkyl or C₁₋₄alkoxy; andAct is an activating group selected from an amino protecting group, inparticular a carbamate; or a salt thereof.

The conversion of a compound of formula (VIII′) to a compound of formula(X′) can proceed according to the methods and conditions as disclosedfor a compound of formula (VIII) above as the starting material.Preferably the reduction is performed with a hydride source understandard conditions. Examples of the hydride source include NaBH₄,LiAlH₄, LiBH₄, Ca(BH₄)₂. Reference is made to the literature citesabove. Particularly preferred are complex hydrides. These are typicallyhydride reagents such as the ones mentioned above, in particular NaBH₄or LiAlH₄, with chiral ligands such as BINOLs, amino acids, chiral aminoalcohols, and other chiral ligands which can form complexes with any ofthe above hydride reagents. For the preferred procedures and conditions,it is referred to:

-   -   1) Org. Proc. Res.& Dev., 4, (2), 107 (2000)    -   2) Heteroatom Chemistry, 14, (7), 603 (2003)    -   3) Synth. Commun., 34, 1359, (2004)    -   4) J. Org. Chem., 61 (24), 8586, (1996)    -   5) J. Org. Chem., 67, (26), 9186, (2002)    -   6) Synthesis, (2), 217 (2004) and the literature cited therein,        all of which are incorporated herein by reference.

The two epimers (syn and anti with respect to the OH group and R3) mayshow different reactivity. Especially, it was found that the anti-epimeris much more reactive in the desired hydrogenolytic cleavage of thebenzylic OH bond with hydrogen and a catalyst such as Pd/C.

Compounds of formula (X′) were found to be important reactants in theabove conversion and, thus, the synthesis of renin inhibitors.Therefore, one aspect of the present invention also is directed tocompounds of formula (X′). Preferred embodiments are the same as forcompound (VIII′). In particular, it is preferred that the compound ofthe formula (X′) is in a salt form as described for the compound offormula (VIII′). The alcohol functionality is typically epimeric andboth epimers can be isolated. Preferably, the compound according to theformula (X′) has the following stereochemistry:

or preferaby a salt thereof, in particular as described herein for thecompound of formula (VIII′). Most preferably, compounds of formula (X′)have the following structure:

or preferably a salt thereof, in particular as described herein for thecompound of formula (VIII′).

The conversion of a compound of formula (X′) to a compound of formula(IX) can proceed according to the methods and conditions as disclosedfor a compound of formula (X) above as the starting material.

Instead of further reducing the compound of formula (X) directly to thecompound of formula (IX), the compound of formula (X) may bealternatively cyclised to a pyrrolidine compound of formula (XI) asshown in Scheme 2:

whereinR³ is C₁₋₇alkyl or C₃₋₈cycloalkyl;R⁴ is C₁₋₇alkyl, C₂₋₇alkenyl, C₃₋₈cycloalkyl, phenyl- ornaphthyl-C₁₋₄alkyl each unsubstituted or mono-, di- or tri-substitutedby C₁₋₄alkyl, O—C₁₋₄alkyl, OH, C₁₋₄alkylamino, halogen and/or bytrifluoromethyl;R¹ is halogen, hydroxyl, C₁₋₆halogenalkyl, C₁₋₆alkoxy-C₁₋₆alkyloxy orC₁₋₆alkoxy-C₁₋₆alkyl;R² is halogen, hydroxyl, C₁₋₄alkyl or C₁₋₄alkoxy; andAct is an activating group selected from an amino protecting group, inparticular a carbamate; or a salt thereof.

Preferred embodiments are the same as for compound (VIII).

Thus in a preferred further embodiment of the invention, this synthesiscomprises as a further step or as an individual synthesis thepreparation a compound of formula (XI)

wherein R³, R⁴, R¹, R² and Act are as defined above, or a salt thereof,comprising cyclisation of the benzylic alcohol and the amine moieties ofthe compound of formula (X) as defined above to a pyrrolidine moiety.This process step as such, also forms an embodiment of the invention.

Preferred embodiments for R³, R⁴ and Act can be taken from thedefinitions for compounds of formula (VI) and preferred embodiments forR¹ and R² can be taken from the definitions for compounds of formula(VIII).

The reaction of the compound of the formula (X) to form the pyrrolidineof formula (XI) preferably takes place under conditions so as to keepthe other functionalities on the molecule intact. It is considered thatduring the reaction protonation of the benzylic alcohol occurs followedby elimination of water to give a benzylic carbocation which is trappedintramolecularly by the nitrogen atom, connected with an Act group suchas a Boc-group or a Cbz-group which is stable under these conditions.The cyclisation is typically effected under acidic conditions. Suitableacids include strong organic or inorganic acids or acidic ion exchangeresins. A suitable strong acid should preferably possess a pKa of <4.75.Preferred are organic acids such as tartaric acid and oxalic acid, oraryl or alkyl sulfonic acids, mineral acids such as phosphoric acid orphosphonic acid, or acidic ion exchange resins such as Amberlyst orDowex, such as Dowex 50WX2-100, 50WX2-200, 50WX2-400, more preferablythe reaction is conducted with an acidic ion exchange resin. When usingan organic or inorganic acid the reaction is preferably conducted underanhydrous conditions. The reaction can be conducted in any suitablesolvent, preferably an inert solvent such as an aromatic or ahalogenated solvent, more preferably methylene chloride or toluene. Thereaction time and the temperature are chosen so as to bring the reactionto completion at a minimum time without the production of unwanted sideproducts. Typically the reaction can be conducted at 0° C. to reflux,preferably 10 to 40° C., more preferably 15-30° C., such as roomtemperature, for 1 min to 12 h, preferably 10 min to 6 h, mostpreferably 30 min to 4 h, such as 2 to 3 h.

The pyrrolidine of formula (XI) is then in another preferred embodimentof the present invention converted to the compound of formula (IX) byreduction or hydrogenation. Thus in a preferred further embodiment ofthe invention, this synthesis comprises as a further step or as anindividual synthesis the preparation of a compound of formula (IX)

wherein R³, R⁴, R¹, R² and Act are as defined above, or a salt thereof,comprising hydrogenation or reduction of the pyrrolidine moiety of thecompound of formula (XI) as defined above to ring-open and to obtain themethylene moiety in position 8. This process step as such, also forms anembodiment of the invention.

The conversion to compound (IX) from compound (XI) can proceed either ina single step or in two or more steps with the corresponding pyrrolidinesalt (XI′) or the pyrrolidine free base (XI″) as an intermediate (seeScheme 2).

When conducting the conversion as a single step, the reaction preferablyutilizes metal initiated reduction. Typical metals employed are alkalineor alkaline earth metals, preferably Li, Na, or Ca. Such reductions aretypically conducted in liquid ammonia or similar reaction conditionslike lower alkyl alcohols or lower alkyl amines as known to the personskilled in the art and as described e.g. Houben-Weyl, Vol. XI/1, page968-975, and also Houben-Weyl, Vol. 4/1c, pp. 645-657, and R. L.Augustine, “Reduktion”, Marcel Dekker, Inc., New York, 1968, “dissolvingmetal reduction”, which are incorporated herein by reference.

When obtaining the compound of formula (IX) via the intermediate (XI′)or (XI″), the pyrrolidine is preferably subjected to hydrogenation.Hydrogenation typically takes place in the presence of a catalystselected from a heterogeneous catalyst. Examples of the catalyst includeRaney nickel, palladium/C, Pd(OH)₂ (Perlman's catalyst), nickel boride,platinum metal or platinum metal oxide, rhodium, ruthenium and zincoxide, more preferably palladium/C, platinum metal or platinum metaloxide, most preferably palladium/C. The catalyst is preferably used inan amount of 1 to 20%, more preferably 5 to 10%. The reaction can beconducted at atmospheric or elevated pressure, such as a pressure of2-10 bar, e.g. 5 bar, more preferably the reaction is conducted atatmopheric pressure. The hydrogenation takes place preferably in aninert solvent, more preferably in tetrahydrofuran, toluene, alcoholssuch as methanol, ethanol and also mixtures of these solvents with waterare possible, most preferably methanol, ethanol and also mixtures ofthese solvents with water. The reaction time and the temperature arechosen so as to bring the reaction to completion at a minimum timewithout the production of unwanted side products. Typically the reactioncan be conducted at 0° C. to reflux, preferably 0 to 100° C., morepreferably 15-70° C., such 30-60° C. or room temperature, for 10 min to12 h, preferably 20 min to 6 h, most preferably 30 min to 4 h, such as 1to 3 h. For more detail reference is made to Tetrahedron, 54, 1753(1998). For other methods see also Houben-Weyl, Vol. 4/1c, Reduktion I,page 400-405, and Houben-Weyl, Vol. XI/1, page 968-975, all of which areincorporated herein by reference.

If during this reaction the Act group is split off, it can bere-introduced as described in the preparation of the compound of formula(VI).

Compounds of formula (XI′) were found to be important reactants in theabove conversion and, thus, the synthesis of renin inhibitors.Therefore, one aspect of the present invention also is directed tocompounds of formula (XI′):

whereinR³ is C₁₋₇alkyl or C₃₋₈cycloalkyl;R⁴ is C₁₋₇alkyl, C₂₋₇alkenyl, C₃₋₈cycloalkyl, pheny-l ornaphthyl-C₁₋₄alkyl each unsubstituted or mono-, di- or tri-substitutedby C₁₋₄alkyl, O—C₁₋₄alkyl, OH, C₁₋₄alkylamino, di-C₁₋₄alkylamino,halogen and/or by trifluoromethyl;R¹ is halogen, hydroxyl, C₁₋₆halogenalkyl, C₁₋₆alkoxy-C₁₋₆alkyloxy orC₁₋₆alkoxy-C₁₋₆alkyl;R² is halogen, hydroxyl, C₁₋₄alkyl or C₁₋₄alkoxy;and X⁻ is an anion such as a halide, trifluoroacetate, sulfate, nitrate,oxalate, sulfonate, triflate, phosphonate or phosphate, preferably ahalide, trifluoroacetate, sulfonate, phosphonate, phosphate or oxalate.

Preferred embodiments for R³ and R⁴ can be taken from the definitionsfor compounds of formula (VI) and preferred embodiments for R¹ and R²can be taken from the definitions for compounds of formula (VIII).

Compounds of formula (XI″) were also found to be important reactants inthe above conversion and, thus, the synthesis of renin inhibitors.Therefore, one aspect of the present invention also is directed tocompounds of formula (XI″):

whereinR³ is C₁₋₇alkyl or C₃₋₈cycloalkyl;R⁴ is C₁₋₇alkyl, C₂₋₇alkenyl, C₃₋₈cycloalkyl, pheny-l ornaphthyl-C₁₋₄alkyl each unsubstituted or mono-, di- or tri-substitutedby C₁₋₄alkyl, O—C₁₋₄alkyl, OH, C₁₋₄alkylamino, di-C₁₋₄alkylamino,halogen and/or by trifluoromethyl;R¹ is halogen, hydroxyl, C₁₋₆halogenalkyl, C₁₋₆alkoxy-C₁₋₆alkyloxy orC₁₋₆alkoxy-C₁₋₆alkyl; andR² is halogen, hydroxyl, C₁₋₄alkyl or C₁₋₄alkoxy.

Preferred embodiments for R³ and R⁴ can be taken from the definitionsfor compounds of formula (VI) and preferred embodiments for R¹ and R²can be taken from the definitions for compounds of formula (VIII).

Instead of further reducing the compound of formula (X) directly to thecompound of formula (IX), the compound of formula (X) may bealternatively converted to an activated compound of formula (X″). Thus,in a further embodiment of the present invention, this synthesiscomprises as a further step or as an individual synthesis thepreparation a compound of formula (X″).

wherein R³ and R⁴ are as defined for a compound of formula (II), R¹ andR² are as defined for a compound of formula (VIII), Act is an activatinggroup selected from an amino protecting group, in particular acarbamate, and Act″ is an electron-withdrawing group, or a salt thereof,comprising conversion of the benzylic alcohol of the compound of formula(X) as defined above to an activated alcohol moiety. This process stepas such as well as the compound of formula (X″), also form an embodimentof the invention.

Preferred embodiments for R³, R⁴ and Act can be taken from thedefinitions for compounds of formula (VI) and preferred embodiments forR¹ and R² can be taken from the definitions for compounds of formula(VIII).

The activating group Act″ should be an electron withdrawing groupaccording to literature (F. J. McQuillin, et al., J. C. S., (C), 136(1967) and Houben-Weyl, Vol. 4/1c, pp 73, 379-383. For exampletrifluoracetyl, or similar electron withdrawing groups. Such electronwithdrawing groups like —CO—CF₃, or —CO—C_(n)F_(m), wherein Cn standsfor a saturated carbon chain of 2 to 8 and m is 1 to 12, enhance thehydrogenolytic cleavage of benzylic carbon-oxygen bonds by a factor30-70 or more compared to nonactivated benzylic OH-groups. Therefore anAct″-group should be of the type Act″=—(C═O)—R⁹, where R⁹ can besubstituted alkyl, alkyl-oxy-R¹⁰, aralkyl, aryl, substituted aryl(especially subst. with EWG-substituents such as F, CF₃, NO₂ or SO₂alkylor SO₂aryl.), O-alkyl, O-aryl, NH—R¹⁰ (where R¹⁰ can be alkyl, aryl,aralkyl, benzyl, benzoyl, subst. sulfonyl. In all cases an EWG moiety,such as one or more F or CF₃, should be part of these residues.

The attachment of an activating group like Act″ can be achieved byreacting com-pounds of type (X) in an aprotic, inert solvent liketoluene, THF, TBME, EtOAc, di-chloromethane, etc. with an acid halide ora symmetrical anhydride of the above mentioned carboxylic acids or mixedanhydrides with other acids, or phosgene derivatives, or carbonates, orisocyanates, or benzoylisocyantes or sulfonylisocyanates.

The compounds of formula (X″) can then be converted to the compounds offormula (IX). Thus in a preferred further embodiment of the invention,this synthesis comprises as a further step or as an individual synthesisthe preparation of a compound of formula (IX)

wherein R³, R⁴, R¹, R² and Act are as defined above, or a salt thereof,comprising hydrogenation or reduction of the activated alcohol moiety ofthe compound of formula (X″) as defined above to obtain the methylenemoiety in position 8. This process step as such, also forms anembodiment of the invention.

The process conditions can be chosen in a similar manner as for theconversion of compound of formula (X) to a compound of formula (IX).

As a further alternative approach, the compound of formula (X) may besubjected to radical-based de-oxygenation (reduction) to yield thecompound of formula (IX). Radical based reductions are less prone tostereochemical differentiation, since usually a planar carbon radicalintermediate is generated, which is reduced by recombination with ahydrogen radical. This leads to similar reducibility of both epimers ofthe compound of formula (X) in this case.

Thus, in an alternative embodiment of the invention, this synthesiscomprises as a further step or as an individual synthesis thepreparation a compound of formula (IX)

wherein R³ and R⁴ are as defined for a compound of formula (II) and Actis an activating group selected from an amino protecting group, inparticular a carbamate, R¹ is halogen, hydroxyl, C₁₋₆halogenalkyl,C₁₋₆alkoxy-C₁₋₆alkyloxy or C₁₋₆alkoxy-C₁₋₆alkyl; R² is halogen,hydroxyl, C₁₋₄alkyl or C₁₋₄alkoxy, or a salt thereof;comprising transformation of the compound of formula (X) as definedherein to a thiocarbonyl derivative and subsequently subjecting same toradical-based reduction to obtain the compound of formula (IX). Thisprocess step as such also forms an embodiment of the invention.

The thiocarbonyl derivative can be any known thiocarbonyl derivativeknown in the art suitable for radical-based de-oxygenation. Preferredexamples are thionocarbamates, such as imidazolyl derivatives,thiocarbonyls, such as xanthates, or thionocarbonates. Particularlypreferred is a thionocabamate of formula (XV)

wherein R³ and R⁴ are as defined for a compound of formula (II) and Actis an activating group selected from an amino protecting group, inparticular a carbamate, R¹ is halogen, hydroxyl, C₁₋₆halogenalkyl,C₁₋₆alkoxy-C₁₋₆alkyloxy or C₁₋₆alkoxy-C₁₋₆alkyl; R² is halogen,hydroxyl, C₁₋₄alkyl or C₁₋₄alkoxy, or a salt thereof.

Compounds of formula (XV), were found to be important reactants in theabove conversion and, thus, the synthesis of renin inhibitors.Therefore, one aspect of the present invention also is directed tocompounds of formula (XV). Preferred embodiments are the same as forcompound (VIII). The alcohol functionality is typically epimeric andboth epimers can be isolated. Preferably, the compound according to theformula (XV) has the following stereochemistry:

For the transformation of the benzylic alcohol to the thioncarbonylderivative, methods known in the art may be employed. Forthionocarbamates, in particular the compound of formula (XV) see e.g.the methods as described in Derek H. R. Barton and Stuart W. McCombie,J. Chem. Soc., Perkin Trans. 1, 1975, 1574, for thiocarbonyls such asxanthates see e.g. Derek H. R. Barton, Doo Ok Jang, Joseph Cs.Jaszberenyi, Tetrahedron Letters 1990, 31, 3991; for thinocarbonates seee.g. M. J. Robins, J. S. Wilson, J. Am. Chem. Soc. 1981, 103, 933 and M.J. Robins, J. S. Wilson, J. Am. Chem. Soc. 1983, 105, 4059.

The radical-based de-oxygenation is performed using standardmethodology, in particular Barton.McCombie conditions as forth in theliterature references for the thiocarbonyl derivative formation. It ispreferred to use either Bu₃SnH or tris(trimethylsilyl)-silane as areducing agent. When tris(trimethylsilyl)silane is used as reducingagent, a tertiary thiol such as dodecyl-mercaptane is added as catalyst.For conditions using the tris(trimethylsilyl)-silane see e.g. DietmarSchummer, Gerhard Höfle, Synlett. 1990, 705. Alternatively, catalyticamounts of Bu₃SnBH in the presence of another reducing agent, e.g. NaBH₄can be employed. Other silanes e.g. phenylsilane, diphenylsilane andtriphenylsilane are also useful for the reduction step, see e.g. D. H.R. Barton, P. Blundell, J. Dorchak, D. O. Jang and, J. Cs. Jaszberenyi,Tetrahedron 1991, 47, 8969; D. H. Barton, D. O. Jang, J. Cs.Jaszberenyi, Tetrahedron 1993, 49, 7193. Additional reducing agents,which have been used in radical based deoxygenations in the literature,such as dialkyl phosphites, hypophosphorous acid and its salts, see e.g.T. Sato, H. Koga, K. Tsuzuki, Heterocycles 1996, 42, 499, as well as2-propanol in the presence of dilauroyl peroxide, see e.g. A. Liard, B.Quicklet-Sire, S. Z. Zard, Tetrahedron Lett. 1996, 37, 5877, are alsouseful to achieve the desired deoxygenation.

It is also possible to directly obtain the compound of formula (X) froma compound of formula (VI) without isolation of any intermediates as aone-pot-synthesis. Thus, in a preferred alternative embodiment of theinvention, this synthesis comprises as a further step or as anindividual synthesis the preparation a compound of formula (X)

wherein R³ and R⁴ are as defined for a compound of formula (II) and Actis an activating group selected from an amino protecting group, inparticular a carbamate, R¹ is halogen, hydroxyl, C₁₋₆halogenalkyl,C₁₋₆alkoxy-C₁₋₆alkyloxy or C₁₋₆alkoxy-C₇₋₆alkyl; R² is halogen,hydroxyl, C₁₋₄alkyl or C₁₋₄alkoxy, or a salt thereof;comprising the step of lactam ring opening of the N-activated lactamlactone of formula (VI) or a salt thereof defined above with a compoundof formula (VII)

wherein Y is a metal containing group such as —Li, —MgX, -magnesates,aryl magnesium species such as

wherein R1 and R2 are as defined herein,alkyl magnesium species, such as branched C₁₋₇alkyl-Mg—, —MnX,(alkyl)₃MnLi—, or —CeX₂ wherein X is halogen such as Cl, I or Br, morepreferably Br; and R¹ and R² are as defined for a compound of formula(X) above, to obtain a compound of formula (VIII′), or a salt thereof,as defined above,followed by reduction of the benzylic carbonyl group of the compound offormula (VIII′) or a salt thereof to obtain a compound of formula (X′),or a salt thereof, as defined above, and lactonization of the compoundof formula (X′) to obtain a compound of formula (X).

This process step as such also forms an embodiment of the invention. Forthis conversion, see also D. Savoia, et al., J. Org. Chem., 54, 228(1989), and literature cited there.

Preferred embodiments for the compounds of formulas (VI), (VII),(VIII′), (X′) and (X) can be taken from the definitions for each ofthese compounds as defined above. Most preferably both compounds (VIII′)and (X′) are used in the salt form, in particular as the Li salt.

For the conversion to a compound of formula (VIII′) to a compound offormula (X) the same or similar methods as described above individuallyfor each conversion can be employed, namely as described for theconversion from a compound of formula (VI) to a compound of formula(VIII) including salt formation to a compound of formula (VIII′), andfurther conversion to a compound of formula (X′). For this last step inparticular the methods as disclosed for the conversion of a compound offormula (VIII′) to a compound of formula (X′) should be emploey,preferably the hydride reduction conditions as mentioned thereinincluding the hydride reagents such as NaBH₄ or LiAlH₄, and also thecomplex hydride conditions described therein. The free acid will formthe lactone moiety of compound (X), preferably by heating the mixture toe.g. 30 to 80° C., more preferably 40 to 60° C., such as 50° C.Typically, acidic conditions, such as mild acidic conditions as known inthe art using e.g. organic acids such as citric acid, are employed forthe lactonization.

In a preferred further embodiment of the invention, this synthesiscomprises as a further step or as an individual synthesis thepreparation a compound of formula (XII)

wherein R³ and R⁴ are as defined for a compound of formula (II), R¹ andR² are as defined for a compound of formula (VIII) and Act is anactivating group selected from an amino protecting group, in particulara carbamate, or a salt thereof, comprising reacting a compound of theformula (IX) as defined above, or a salt thereof, with an amine of theformula (XIII),

(wherein the amido nitrogen can also be protected if desired and theprotecting group then be removed in the corresponding protected compoundof the formula XII), or a salt thereof. This process step as such alsoforms an embodiment of the invention.

This conversion can proceed according to typical peptide couplingreactions well known in the art, e.g. in analogy to the processdisclosed in EP-A-678 503 which is incorporated herein by reference, seein particular examples 124 and 131 or as disclosed in WO 02/02508, whichis incorporated herein by reference, in particular example H1 on page 35(preparation of J1).

Preferred embodiments for R³, R⁴ and Act can be taken from thedefinitions for compounds of formula (VI) and preferred embodiments forR¹ and R² and Act can be taken from the definitions for compounds offormula (VIII). Preferably, the compound according to the formula (XII)has the following stereochemistry:

The reaction preferably takes place under standard conditions for theformation of an amide from a lactone, e.g. in an appropriate solvent orsolvent mixture, e.g. in an ether, such as tert-butylmethyl ether,preferably in the presence of a bifunctional catalyst with a weak acidicand a weak basic group, e.g. 2-hydroxypyridine or proline, in thepresence of an appropriate base, e.g. a tertiary nitrogen base, such astriethylamine, at appropriate temperatures e.g. in the range from 0° C.to the reflux temperature of the reaction mixture, e.g. from 0 to 85° C.

The amide coupling to compound (XII) using a compound of formula (XIII)as described above can also proceed in a similar manner as disclosedabove using the ring-opened analogue of a compound of formula (IX).Thus, this reaction may proceed in using the corresponding compound ofthe formula (IX′) as a starting material

whereinR³ is C₁₋₇alkyl or C₃₋₈cycloalkyl;R⁴ is C₁₋₇alkyl, C₂₋₇alkenyl, C₃₋₈cycloalkyl, phenyl- ornaphthyl-C₁₋₄alkyl each unsubstituted or mono-, di- or tri-substitutedby C₁₋₄alkyl, O—C₁₋₄alkyl, OH, C₁₋₄alkylamino, di-C₁₋₄alkylamino,halogen and/or by trifluoromethyl;R¹ is halogen, hydroxyl, C₁₋₆halogenalkyl, C₁₋₆alkoxy-C₁₋₆alkyloxy orC₁₋₆alkoxy-C₁₋₆alkyl;R² is halogen, hydroxyl, C₁₋₄alkyl or C₁₋₄alkoxy; andAct is an activating group selected from an amino protecting group, inparticular a carbamate; or a salt thereof. This process step as suchalso forms an embodiment of the invention.

The conversion of a compound of formula (IX) to a compound of formula(IX′) can proceed according to the methods and conditions as disclosedfor the lactone ring opening of a compound of formula (II) above to acompound of formula (II′). It is recommended to protect the alcoholmoiety of the compound of formula (IX′) prir to the amide couplingreaction, Standard alcohol protection/deprotection chemistry can beemployed.

Compounds of formula (IX′) were found to be important reactants in theabove conversion and, thus, the synthesis of renin inhibitors.Therefore, one aspect of the present invention also is directed tocompounds of formula (IX′). Preferred embodiments are the same as forcompound (VIII′). In particular, it is preferred that the compound ofthe formula (IX′) is in a salt form as described for the compound offormula (VIII′). Preferably, the compound according to the formula (X′)has the following stereochemistry:

or preferaby a salt thereof, in particular as described herein for thecompound of formula (VIII′). Most preferably, compounds of formula (IX′)have the following structure:

or preferably a salt thereof, in particular as described herein for thecompound of formula (VIII′).

The conversion of a compound of formula (IX′) to a compound of formula(XII) can proceed according to the methods and conditions as disclosedfor a compound of formula (IX) above as the starting material.

Compounds of formula (XII) may then be converted into a compound offormula (XIV)

wherein R³ and R⁴ are as defined for a compound of formula (II), R¹ andR² are as defined for a compound of formula (VIII), or a salt thereof,said conversion comprising removing the activating group Act; and, ifdesired, converting an obtainable free compound of the formula XIV intoa salt (which is preferred) or an obtainable salt into the free compoundof the formula XIV or a different salt thereof. For example, if Act is(what is preferred) a C₁-C₇-alkoxycarbonyl group, such astert-butoxycarbonyl, the removal can take place under customaryconditions, e.g. in the presence of an acid, such as hydrohalic acid, inan appropriate solvent, such as dioxane, e.g. at temperatures from 0 to50° C., for example at room temperature. The removal of the group Act isperformed using standard protecting group chemistry following theprocedures as described in the literature referenced below or usingmethods well known in the art, see e.g. EP-A-0678 503, which isincorporated herein by reference, in particular example 130, andoptionally salt formation using reaction conditions as described e.g. inU.S. Pat. No. 5,559,111, which is incorporated herein by reference, seein particular example 83.

Each of the above mentioned method steps can be used individually in amethod to prepare renin inhibitors such as aliskiren. Preferably thesteps are used in combination of one or more, most preferably all, toprepare renin inhibitors such as aliskiren.

Preferred embodiments for R³, R⁴ and Act can be taken from thedefinitions for compounds of formula (VI) and preferred embodiments forR¹ and R² and Act can be taken from the definitions for compounds offormula (VIII). Most preferably the compound is aliskiren.

All these different synthesis steps and routes show that with compoundsof the formula (II) and (VI) highly important new compounds have beenfound that are central intermediates to a number of possible synthesisroutes especially for the synthesis of renin inhibitors such asaliskiren. Therefore, these compounds of the formula (II) and (VI), or asalt thereof, as well as their syntheses form very highly preferredembodiments of the invention.

Listed below are definitions of various terms used to describe the novelintermediates and synthesis steps of the present invention. Thesedefinitions, either by replacing one, more than one or all generalexpressions or symbols used in the present disclosure and thus yieldingpreferred embodiments of the invention, preferably apply to the terms asthey are used throughout the specification unless they are otherwiselimited in specific instances either individually or as part of a largergroup.

The term “lower” or “C₁-C₇-” defines a moiety with up to and includingmaximally 7, especially up to and including maximally 4, carbon atoms,said moiety being branched (one or more times) or straight-chained andbound via a terminal or a non-terminal carbon. Lower or C₁-C₇-alkyl, forexample, is n-pentyl, n-hexyl or n-heptyl or preferably C₁-C₄-alkyl,especially as methyl, ethyl, n-propyl, sec-propyl, n-butyl, isobutyl,sec-butyl, tert-butyl.

Halo or halogen is preferably fluoro, chloro, bromo or iodo, mostpreferably fluoro, chloro or bromo; where halo is mentioned, this canmean that one or more (e.g. up to three) halogen atoms are present, e.g.in halo-C₁-C₇-alkyl, such as trifluoromethyl, 2,2-difluoroethyl or2,2,2-trifluoroethyl.

Alkyl preferably has up to 20 carbon atom and is more preferablyC₁-C₇-alkyl. Alkyl is straight-chained or branched (one or, if desiredand possible, more times). Very preferred is methyl.

Halogenalkyl may be linear or branched and preferably comprise 1 to 4 Catoms, especially 1 or 2 C atoms. Examples are fluoromethyl,difluoromethyl, trifluoromethyl, chloromethyl, dichloromethyl,trichloromethyl, 2-chloroethyl and 2,2,2-trifluoroethyl.

Branched alkyl preferably comprises 3 to 6 C atoms. Examples arei-propyl, i- and t-butyl, and branched isomers of pentyl and hexyl.

Cycloalkyl preferably comprises 3 to 8 ring-carbon atoms, 3 or 5 beingespecially preferred. Some examples are cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl and cyclooctyl. The cycloalkyl may optionally besubstituted by one or more substituents, such as alkyl, halo, oxo,hydroxy, alkoxy, amino, alkylamino, dialkylamino, thiol, alkylthio,nitro, cyano, heterocyclyl and the like.

Alkenyl may be linear or branched alkyl containing a double bond andcomprising preferably 2 to 12 C atoms, 2 to 8 C atoms being especiallypreferred. Particularly preferred is a linear C₂₋₄alkenyl. Some examplesof alkyl groups are ethyl and the isomers of propyl, butyl, pentyl,hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tetradecyl,hexadecyl, octacyl and eicosyl, each of which containing a double bond.Especially preferred is allyl.

Alkylamino and dialkylamino may be linear or branched. Some examples aremethylamino, dimethylamino, ethylamino, and diethylamino.

Alkoxy-alkyloxy may be linear or branched. The alkoxy group preferablycomprises 1 to 4 and especially 1 or 2 C atoms, and the alkyloxy grouppreferably comprises 1 to 4 C atoms. Examples are methoxymethyloxy,2-methoxyethyloxy, 3-methoxypropyloxy, 4-methoxybutyloxy,5-methoxypentyloxy, 6-methoxyhexyloxy, ethoxymethyloxy,2-ethoxyethyloxy, 3-ethoxypropyloxy, 4-ethoxybutyloxy,5-ethoxypentyloxy, 6-ethoxyhexyloxy, propyloxymethyloxy,butyloxymethyloxy, 2-propyloxyethyloxy and 2-butyloxyethyloxy.

Alkoxyalkyl may be linear or branched. The alkoxy group preferablycomprises 1 to 4 and especially 1 or 2 C atoms, and the alkyl grouppreferably comprises 1 to 4 C atoms. Examples are methoxymethyl,2-methoxyethyl, 3-methoxypropyl, 4-methoxybutyl, 5-methoxypentyl,6-methoxyhexyl, ethoxymethyl, 2ethoxyethyl, 3-ethoxypropyl,4-ethoxybutyl, 5-ethoxypentyl, 6-ethoxyhexyl, propyloxymethyl,butyloxymethyl, 2-propyloxyethyl and 2-butyloxyethyl.

Alkoxy may be linear or branched and preferably comprise 1 to 4 C atoms.Examples are methoxy, ethoxy, n- and i-propyloxy, n-, i- and t-butyloxy,pentyloxy and hexyloxy.

Protecting groups may be present (see also under “General ProcessConditions”) and should protect the functional groups concerned againstunwanted secondary reactions, such as acylations, etherifications,esterifications, oxidations, solvolysis, and similar reactions. It is acharacteristic of protecting groups that they lend themselves readily,i.e. without undesired secondary reactions, to removal, typically bysolvolysis, reduction, photolysis or also by enzyme activity, forexample under conditions analogous to physiological conditions, and thatthey are not present in the end-products. The specialist knows, or caneasily establish, which protecting groups are suitable with thereactions mentioned hereinabove and hereinafter. Preferably, if two ormore protecting groups are present in one intermediate mentioned herein,they are chosen so that, if one of the groups needs to be removed, thiscan be done selectively, e.g. using two or more different protectinggroups that are cleavable under different conditions, e.g. one class bymild hydrolysis, the other by hydrolysis under harder conditions, oneclass by hydrolysis in the presence of an acid, the other by hydrolysisin the presence of a base, or one class by reductive cleavage (e.g. bycatalytic hydrogenation), the other by hydrolysis, or the like.

As hydroxyl protecting group, any group that is appropriate forreversible protection of hydroxy groups is possible, e.g. thosementioned in the standard textbooks under “General Process Conditions”.A hydroxyl protecting group may, just to mention a few examples, beselected from a group comprising (especially consisting of) a silylprotecting group, especially diaryl-lower alkyl-silyl, such asdiphenyl-tert-butylsilyl, or more preferably tri-lower alkylsilyl, suchas tert-butyldimethylsilyl or trimethylsilyl; an acyl group, e.g. loweralkanoyl, such as acetyl; benzoyl; lower alkoxycarbonyl, such astert-butoxycarbonyl (Boc), or phenyl-lower alkoxycarbonyl, such asbenzyloxycarbonyl; tetrahydropyranyl; unsubstituted or substituted1-phenyl-lower alkyl, such as benzyl or p-methoxybenzyl, andmethoxymethyl. Boc (selectively removable by hydrolysis) and benzyl(selectively removable by hydrogenation) are especially preferred.

As amino protecting group, any group that is appropriate for reversibleprotection of hydroxy groups is possible, e.g. those mentioned in thestandard textbooks under “General Process Conditions”. An aminoprotecting group may, just to mention a few examples, be selected from agroup comprising (especially consisting of) acyl (especially the residueof an organic carbonic acid bound via its carbonyl group or an organicsulfonic acid bound via its sulfonyl group), arylmethyl, etherifiedmercapto, 2-acyl-lower alk-1-enyl, silyl or N-loweralkylpyrrolidinylidene. Preferred amino-protecting groups are loweralkoxycarbonyl, especially tert-butoxycarbonyl (Boc), phenyl-loweralkoxycarbonyl, such as benzyloxycarbonyl, fluorenyl-loweralkoxycarbonyl, such as fluorenylmethoxycarbonyl, 2-lower alkanoyl-loweralk-1-en-2-yl and lower alkoxycarbonyl-lower alk-1-en-2-yl, with mostpreference being given to isobutyryl, benzoyl, phenoxyacetyl,4-tert-butylphenoxyacetyl, N,N-dimethylformamidinyl,N-methylpyrrolidin-2-ylidene or especially tert-butoxycarbonyl.

Unsubstituted or substituted aryl is preferably a mono- or polycyclic,especially monocyclic, bicyclic or tricyclic aryl moiety with 6 to 22carbon atoms, especially phenyl (very preferred), naphthyl (verypreferred), indenyl, fluorenyl, acenapthylenyl, phenylenyl orphenanthryl, and is unsubstituted or substituted by one or more,especially one to three, moieties, preferably independently selectedfrom the group consisting of C₁-C₇alkyl, C₁-C₇alkenyl, C₁-C₇alkynyl,halo-C₁-C₇alkyl, such as trifluoromethyl, halo, especially fluoro,chloro, bromo or iodo, hydroxy, C₁-C₇-alkoxy, phenyloxy, naphthyloxy,phenyl- or naphthyl-C₁-C₇-alkoxy, C₁-C₇alkanoyloxy, phenyl- ornaphthyl-C₁-C₇-alkanoyloxy, amino, mono- or di-(C₁-C₇alkyl, phenyl,naphthyl, phenyl-C₁-C₇-alkyl, naphthyl-C₁-C₇-alkyl, C₁-C₇-alkanoyland/or phenyl- or naphthyl-C₁-C₇-alkanoyl)-amino, carboxy,C₁-C₇-alkoxycarbonyl, phenoxycarbonyl, naphthyloxycarbonyl,phenyl-C₁-C₇-alkyloxycarbonyl, naphthyl-C₁-C₇-alkoxycarbonyl, carbamoyl,N-mono- or N,N-di-(C₁-C₇-alkyl, phenyl, naphthyl, phenyl-C₁-C₇alkyland/or naphthyl-C₁-C₇alkyl)-aminocarbonyl, cyano, sulfo, sulfamoyl,N-mono- or N,N-di-(C₁-C₇-alkyl, phenyl, naphthyl, phenyl-C₁-C₇alkyland/or naphthyl-C₁-C₇-alkyl)-aminosulfonyl and nitro.

Salts are especially the pharmaceutically acceptable salts of compoundsof formula XIV or generally salts of any of the intermediates mentionedherein, where salts are not excluded for chemical reasons the skilledperson will readily understand. They can be formed where salt forminggroups, such as basic or acidic groups, are present that can exist indissociated form at least partially, e.g. in a pH range from 4 to 10 inaqueous solutions, or can be isolated especially in solid, especiallycrystalline, form.

Such salts are formed, for example, as acid addition salts, preferablywith organic or inorganic acids, from compounds of formula XIV or any ofthe intermediates mentioned herein with a basic nitrogen atom (e.g.imino or amino), especially the pharmaceutically acceptable salts.Suitable inorganic acids are, for example, halogen acids, such ashydrochloric acid, sulfuric acid, or phosphoric acid. Suitable organicacids are, for example, carboxylic, phosphonic, sulfonic or sulfamicacids, for example acetic acid, propionic acid, lactic acid, fumaricacid, succinic acid, citric acid, amino acids, such as glutamic acid oraspartic acid, maleic acid, hydroxymaleic acid, methylmaleic acid,benzoic acid, methane- or ethanesulfonic acid, ethane-1,2-disulfonicacid, benzenesulfonic acid, 2-naphthalenesulfonic acid,1,5-naphthalene-disulfonic acid, N-cyclohexylsulfamic acid, N-methyl-,N-ethyl- or N-propyl-sulfamic acid, or other organic protonic acids,such as ascorbic acid.

In the presence of negatively charged radicals, such as carboxy orsulfo, salts may also be formed with bases, e.g. metal or ammoniumsalts, such as alkali metal or alkaline earth metal salts, for examplesodium, potassium, magnesium or calcium salts, or ammonium salts withammonia or suitable organic amines, such as tertiary monoamines, forexample triethylamine or tri(2-hydroxyethyl)amine, or heterocyclicbases, for example N-ethyl-piperidine or N,N′-dimethylpiperazine.

When a basic group and an acid group are present in the same molecule, acompound of formula XIV or any of the intermediates mentioned herein mayalso form internal salts.

For isolation or purification purposes of compounds of the formula XIVor in general for any of the intermediates mentioned herein it is alsopossible to use pharmaceutically unacceptable salts, for examplepicrates or perchlorates. For therapeutic use, only pharmaceuticallyacceptable salts or free compounds of the formula XIV are employed(where applicable comprised in pharmaceutical preparations), and theseare therefore preferred at least in the case of compounds of the formulaXIV.

In view of the close relationship between the compounds andintermediates in free form and in the form of their salts, includingthose salts that can be used as intermediates, for example in thepurification or identification of the compounds or salts thereof, anyreference to “compounds”, “starting materials” and “intermediates”hereinbefore and hereinafter, especially to the compound(s) of theformula XIV, is to be understood as referring also to one or more saltsthereof or a mixture of a corresponding free compound, intermediate orstarting material and one or more salts thereof, each of which isintended to include also any solvate, metabolic precursor such as esteror amide of the compound of formula XIV, or salt of any one or more ofthese, as appropriate and expedient and if not explicitly mentionedotherwise. Different crystal forms may be obtainable and then are alsoincluded.

Where the plural form is used for compounds, starting materials,intermediates, salts, pharmaceutical preparations, diseases, disordersand the like, this is intended to mean one (preferred) or more singlecompound(s), salt(s), pharmaceutical preparation(s), disease(s),disorder(s) or the like, where the singular or the indefinite article(“a”, “an”) is used, this is not intended to exclude the plural, butonly preferably means “one”.

Starting materials are especially the compounds of the formula I, III,VII and/or XIII mentioned herein, intermediates are especially compoundsof the formula II, II′, IV, V, VI, VIII, VIII′, IX, IX′, X, X′, X″, XI,XI′, XI″, XII and/or. XV.

The invention relates also to methods of synthesis of the intermediatesof the formula II, II′, IV, V, VI, VIII, VIII′, IX, IX′, X, X′, X″, XI,XI′, XI″, XII and/or. XV mentioned above from their respectiveprecursors as mentioned above, including methods with the single stepsof a sequence leading to a compound of the formula XIV, more than one orall steps of said synthesis and/or pharmaceutically active substances,especially renin inhibitors, most preferably aliskiren, includingmethods with the single steps of a sequence leading to a compound of theformula XIV, more than one or all steps of said synthesis and/orpharmaceutically active substances, and/or their use in the synthesis ofpharmaceutically active compounds, such as renin inhibitors, especiallyaliskiren.

General Process Conditions

The following, in accordance with the knowledge of a person skilled inthe art about possible limitations in the case of single reactions,applies in general to all processes mentioned hereinbefore andhereinafter, while reaction conditions specifically mentioned above orbelow are preferred:

In any of the reactions mentioned hereinbefore and hereinafter,protecting groups may be used where appropriate or desired, even if thisis not mentioned specifically, to protect functional groups that are notintended to take part in a given reaction, and they can be introducedand/or removed at appropriate or desired stages. Reactions comprisingthe use of protecting groups are therefore included as possible whereverreactions without specific mentioning of protection and/or deprotectionare described in this specification. Within the scope of this disclosureonly a readily removable group that is not a constituent of theparticular desired end product of formula XIV is designated a“protecting group”, unless the context indicates otherwise. Theprotection of functional groups by such protecting groups, theprotecting groups themselves, and the reactions appropriate for theirintroduction and removal are described for example in standard referenceworks, such as J. F. W. McOmie, “Protective Groups in OrganicChemistry”, Plenum Press, London and New York 1973, in T. W. Greene andP. G. M. Wuts, “Protective Groups in Organic Synthesis”, Third edition,Wiley, New York 1999, in “The Peptides”; Volume 3 (editors: E. Gross andJ. Meienhofer), Academic Press, London and New York 1981, in “Methodender organischen Chemie” (Methods of Organic Chemistry), Houben Weyl, 4thedition, Volume 15/I, Georg Thieme Verlag, Stuttgart 1974, in H.-D.Jakubke and H. Jeschkeit, “Aminosäuren, Peptide, Proteine” (Amino acids,Peptides, Proteins), Verlag Chemie, Weinheim, Deerfield Beach, and Basel1982, in “Protecting Groups”, Philip J. Kocienski, 3rd Edition,GeorgThieme Verlag, Stuttgart, ISBN 3-13-137003-3 and in Jochen Lehmann,“Chemie der Kohlenhydrate: Monosaccharide and Derivate” (Chemistry ofCarbohydrates: Monosaccharides and Derivatives), Georg Thieme Verlag,Stuttgart 1974, all of which are incorporated herein by reference. Acharacteristic of protecting groups is that they can be removed readily(i.e. without the occurrence of undesired secondary reactions) forexample by solvolysis, reduction, photolysis or alternatively underphysiological conditions (e.g. by enzymatic cleavage). Differentprotecting groups can be selected so that they can be removedselectively at different steps while other protecting groups remainintact. The corresponding alternatives can be selected readily by theperson skilled in the art from those given in the standard referenceworks mentioned above or the description or the Examples given herein.

All the above-mentioned process steps can be carried out under reactionconditions that are known per se, preferably those mentionedspecifically, in the absence or, customarily, in the presence ofsolvents or diluents, preferably solvents or diluents that are inerttowards the reagents used and dissolve them, in the absence or presenceof catalysts, condensation or neutralizing agents, for example ionexchangers, such as cation exchangers, e.g. in the H⁺ form, depending onthe nature of the reaction and/or of the reactants at reduced, normal orelevated temperature, for example in a temperature range of from about−100° C. to about 190° C., preferably from approximately −80° C. toapproximately 150° C., for example at from −80 to −60° C., at roomtemperature, at from −20 to 40° C. or at reflux temperature, underatmospheric pressure or in a closed vessel, where appropriate underpressure, and/or in an inert atmosphere, for example under an argon ornitrogen atmosphere.

The solvents from which those solvents that are suitable for anyparticular reaction may be selected include those mentioned specificallyor, for example, water, esters, such as lower alkyl-lower alkanoates,for example ethyl acetate, ethers, such as aliphatic ethers, for examplediethyl ether, or cyclic ethers, for example tetrahydrofurane ordioxane, liquid aromatic hydrocarbons, such as benzene or toluene,alcohols, such as methanol, ethanol or 1- or 2-propanol, nitriles, suchas acetonitrile, halogenated hydrocarbons, e.g. as methylene chloride orchloroform, acid amides, such as dimethylformamide or dimethylacetamide, bases, such as heterocyclic nitrogen bases, for examplepyridine or N-methylpyrrolidin-2-one, carboxylic acid anhydrides, suchas lower alkanoic acid anhydrides, for example acetic anhydride, cyclic,linear or branched hydrocarbons, such as cyclohexane, hexane orisopentane, or mixtures of these, for example aqueous solutions, unlessotherwise indicated in the description of the processes. Such solventmixtures may also be used in working up, for example by chromatographyor partitioning. Where required or desired, water-free or absolutesolvents can be used.

Where required, the working-up of reaction mixtures, especially in orderto isolate desired compounds or intermediates, follows customaryprocedures and steps, e.g. selected from the group comprising but notlimited to extraction, neutralization, crystallization, chromatography,evaporation, drying, filtration, centrifugation and the like.

The invention relates also to those forms of the process in which acompound obtainable as intermediate at any stage of the process is usedas starting material and the remaining process steps are carried out, orin which a starting material is formed under the reaction conditions oris used in the form of a derivative, for example in protected form or inthe form of a salt, or a compound obtainable by the process according tothe invention is produced under the process conditions and processedfurther in situ. In the process of the present invention those startingmaterials are preferably used which result in compounds of formula XIVwhich are described as being preferred. Special preference is given toreaction conditions that are identical or analogous to those mentionedin the Examples. The invention relates also to novel starting compoundsand intermediates described herein, especially those leading tocompounds mentioned as preferred herein.

The invention especially relates to any of the methods describedhereinbefore and hereinafter that leads to aliskiren, or apharmaceutically acceptable salt thereof.

The following Examples serve to illustrate the invention withoutlimiting the scope thereof, while they on the other hand representpreferred embodiments of the reaction steps, intermediates and/or theprocess of manufacture of aliskiren, or salts thereof.

Where mentioned in the Examples, “boc” stands for tert-butoxycarbonyl.

EXAMPLES 1) Preparation of Lactam Lactone of Formula (II) Via Anhydride[3-Isopropyl-5-(4-isopropyl-5-oxo-tetrahydro-furan-2-yl)pyrrolidin-2-one](IIa)

26.45 g (88.9 mmol) of compound IIIa, are dissolved in 150 ml oftoluene.

10.35 g (102.3 mmol) of triethylamine are dissolved in 10 ml of tolueneand added to the solution of starting material at room temperature. Thissolution is then cooled down to 0-5° C. At this temperature a solutionof 13.97 g isobutyl-chloroformate dissolved in 10 ml of toluene is addedover 25 minutes. After 30 min. stirring at 0-5° C. the suspension isallowed to warm up to room temperature.

The reaction vessel is transfered to the hydrogenation station and ishydrogenated there by addition of 5 g Pd/C, 5%, Engelhard 4522. After 21hours the reaction suspension is then filtered. The filtrate is dilutedwith 150 ml of water and the organic phase is separated. After washingwith water the organic layer is evaporated. The crude material isdissolved at reflux in 40 ml of ethyl acetate and 20 ml of heptane untila clear solution is obtained. The solution is allowed to cool down toroom temperature. The crystallization starts almost immediately and wascompleted by stirring for further 21 hours at 23-25° C. The suspensionis cooled down to 0-5° C. and stirring is continued for additional 3 hat this temperature. After filtration the product IIa is washed with 30ml of a cold mixture of heptane/ethyl acetate 2:1 and dried under vacuumat 40° C.

A single crystal X-ray determination confirms the absolute configurationat all 4 stereo centers to be (S,S,S,S).

Mp: 136-138° C., clear, colorless

¹H-NMR (400 MHz, CDCl₃): 6.04 (s, 1H), 4.22-4.16 (m, 1H), 3.51-3.46 (m,1H), 2.55-2.51 (m, 1H), 2.44-2.38 (m, 1H), 2.17-2.09 (m, 3H), 2.07-1.99(m, 1H), 1.94-1.87 (m, 1H), 1.80-1.73 (m, 1H) 0.99-0.97 (d, 3H),0.95-0.93 (d, 3H), 0.91-0.89 (d, 3H), 0.85-0.84 (d, 3H)

MS: MH⁺=254

IR: 1775=Lacton, 1704=Lactam, cm⁻¹ (FTIR-Microscopy in transmission)

2) Alternative Preparation of Lactam Lactone of Formula (II) Via DirectHydrogenation[3-Isopropyl-5-(4-isopropyl-5-oxo-tetrahydro-furan-2-yl)pyrrolidin-2-one](IIa)

9.0 g (19.7 mmol) of compound Ia and 1.08 g of palladium/C (5%) togetherwith 55 ml of toluene are charged to a hydrogenation flask. Thehydrogenation is performed at room temperatur and normal pressure. After24 hours the conversion is controlled and is complete. The reactionmixture is filtered through a bed of a filter aid and washed withtoluene to remove the catalyst. The toluene is evaporated in vacuum togive a white crystalline solid which consists as a mixture of compoundIIa and the Evans auxiliary. To separate the desired compound IIa fromthe auxiliary the crystalline solid (9.03 g) is dissolved in 50 ml oftoluene. To the resulting clear, colourless solution is added at roomtemperature 20 ml of 2N sodium hydroxide solution. The resultingemulsion is stirred at room temperature for 1 hour. The desired productis now in the basic aqueous phase as the sodium salt and the auxiliarystays in the toluene phase. The aqueous phase is washed 3-times with 20ml of toluene to completely extract the auxiliary. The aqueous phase isthen acidified with 70 ml of 10% citric acid to adjust the pH to 3.During acidification the lactam hydroxyl acid II′a is precipitated.After stirring for an additional 30 min. the crystals are filtered anddried in vacuum to give a white crystalline powder of compound II′a.

m.p.: 152-155° C.

¹H-NMR (DMSO-d₆): 0.78 (d, 3H), 0.87-0.91 (3×d, 9H), 1.36 (m, 1H), 1.52(m, 1H), 1.72-1.85 (cm, 3H), 1.91-1.98 (m, 1H), 2.19-2.24 (m, 1H),2.33-2.38 (m, 1H), 3.10-3.18 (m, 1H), 3.21-3.25 (m, 1H), 4.73 (broad,1H, —OH), 7.55 (bs, 1H, NH), 12.03 (broad, 1H, CO₂H).

IR: 1730, 1702, 1661, cm⁻¹ (FTIR-Microscopy in transmission)

MS: MH⁺=272

The compound II′a (3.65 g) is then again dissolved in toluene andtreated with catalytic amounts of p-toluene sulfonic acid mono hydrate(0.25 g) at 50° C. After 5 h (tic control) the acid is converted to thedesired lactam-lactone IIa. The toluene phase is extracted twice with 50ml of water and the toluene phase is then evaporated in vacuum to giveafter drying the white, crystalline compound IIa with a melting point of136-138° C. The spectroscopic data are identical with the material ofexample No. 1).

3) Preparation of “Azido Acid” Methylester of Formula (Va)

3.0 g (10.1 mmol) of IIIa are dissolved in 15 ml of dichloromethane atroom temperature. 1.66 g (11.1 mmol) 3-methyl-1-p-tolyltriazene is addedat room temperature over 25 min. After the addition the reactionsolution was allowed to stirr at 20-25° C. over a period of 2 hours.During the reaction nitrogen gas is produced. For work up 30 ml of waterare added to the solution. The organic phase is washed with 30 ml of 1NHCl (2×15 ml) and 30 ml NaHCO₃ 8% (2×15 ml). The organic phase is washedto a neutral pH with 45 ml of water (3×15 ml) and evaporated to yield Vaas a yellow oil which crystallizes in the refrigerator.

¹H-NMR (400 MHz, CDCL₃): 4.40-4.36 (m, 1H), 3.70 (s, 3H), 3.18-3.13 (m,1H), 2.68-2.62 (m, 1H), 2.52-2.47 (m, 1H), 2.18-2.10 (m, 3H), 1.98-1.93(q, 1H), 1.89-1.82 (m, 1H), 1.74-1.67 (m, 1H), 1.02-1.00 (d, 3H),0.94-0.91 (m, 9H)

GC/MS: MH⁺=312

3b) Hydrogenation of “Azido Acid” Methylester of Formula (Va) to (IIa)

1.5 g of (Va) (4.8 mmol) are dissolved in 15 ml of toluene. 0.3 of Pd/C,(5%), catalyst (Engelhard 4522) are added and hydrogenation is performedat room temperature and normal pressure over 24 hours after whichhydrogen uptake was complete. The catalyst is filtered and the filtrateis evaporated in vacuum to give a white powder, which is identicalaccording to ¹H-NMR, IR and Tlc to compound (IIa).

4) Preparation of Boc-Protected Lactam-Lactone of Formula (VIa)

14 g Lactam-lactone IIa (55.3 mmol) and 6.7 mg dimethyl-amino-pyridine(0.055 mmol) are dissolved together in 100 ml of isopropyl acetate. Tothis solution is added 5.6 g (55.3 mmol) of triethylamine. This solutionis warmed at internal temperature 40-45° C. At this temperature asolution of 13.3 g (60.8 mmol) di-tert-butyl-dicarbonate in 60 mlisopropyl acetate is added over a time of 30 min. The reaction solutionis allowed to stir overnight at 40-45° C.

After this time the reaction solution is cooled down to room temperatureand diluted with 160 ml of heptane. The suspension is then cooled downto 0-5° C. and stirring is continued at this temperature for 5 hours.After filtration the product cake is washed with 50 ml of coldheptane/ethyl acetate and dried under vacuum at 40° C.

¹H-NMR (400 MHz, CDCl₃): 4.52-4.48 (m, 1H, 4.34-4.29 (m, 1H), 2.68-2.62(m, 1H), 2.55-2.49 (m, 1H), 2.24-2.08 (m, 4H), 2.03-1.94 (m, 1H),1.81-1.75 (m, 1H), 1.52 (s, 9H), 1.02-0.98 (pst, 6H), 0.92-0.91 (d, 3H,0.85-0.84 (d, 3H)

MS: MH⁺=354

IR: 1777-1760 Lactam/Lacton/Boc, 1185 Boc cm⁻¹ (FTIR-Microscopy intransmission)

Mp: 144-145° C., clear, colorless

5) Reaction of Boc-Lactam-Lactone (VIa) with Aryl-Li-Compound (VIIa) toCompound (VIIIa)

8.56 g (31.12 mmol) aryl bromide (VII′a) are dissolved in 125 ml of THFin a first flask. The solution is cooled at internal temperature of −70°C. To this solution id added over a time of 1 hour 19.8 ml (31.69 mmol)n-butyllithium, 1.6 M solution in hexane. The reaction solution becamethen a pink-red color. The solution is allowed to stir for 1 hour at−70° C. 10.0 g Boc-lactam-lacton (VIa) (28.29 mmol) are dissolved in 125ml of dry THF in a second flask. The solution is cooled at internaltemperature −50° C. under a stream of argon. To this solution is addedthe solution of aryl-lithium compound (VIIa) (from flask N^(o) 1) at −55to −50° C. over a time of 30 minutes.

The reaction mixture is stirred then at −50° C. over 3 hours. Thereaction is cooled to a temperature of −70° C. over night.

The next day a second part of aryl-lithium compound is prepared with1.28 g aryl bromide, (VII′a), (4.65 mmol) and 3 ml of n-butyllithium inthe same manner as described, and added at internal temperature of −50°C. during a time of 10 minutes to the reaction mixture. The reactionmixture is allowed to stir for 4 hours at −50° C.

For work up the reaction mixture is put on a mixture of 125 ml oftoluene and 250 ml of a 10% citric acid solution in water at 0-5° C.during 20 minutes. The quenching is exothermic. The organic phase iswashed with 150 ml citric acid, 10% in water, (2×75 ml) and 150 mlNaHCO_(3 [)8%], (2×75 ml). The organic phase is washed to a neutral pHwith 150 ml of water (2×75 ml) and evaporated to yield crude compound(VIIIa) as a nearly white amorphous solid.

To purify the desired compound a part of the solid (6.72 g, 12.22 mmol)is dissolved in 60 ml of ethanol. To the resulting clear colorlesssolution are added at 0-5° C. 28 ml of 1N lithium hydroxide solutionover a time of 20 minutes. This mixture is allowed to warm up to roomtemperature (21° C.) and stir at this temperature over a period of 1hour. After this time water and ethanol is partially evaporated and theresulting precipitate is diluted with 100 ml of water and 50 ml oftoluene to give a clear solution. The desired product is now in thebasic aqueous phase. The water phase is washed with 150 ml of toluene(3×50 ml). To the water phase is added 75 ml of ethyl acetate. To thisreaction mixture 7.1 g (33.66 mmol) of citric acid are added. Theprotonated product is now in the organic phase. The mixture is allowedto stir at room temperature at the be-ginning, then later at 50° C.After 12 hours stirring, 3.6 g citric acid (17.1 mmol) are added to themixture and stirring is continued at 50° C. during 24 h. The water phaseis then separated and 7.1 g citric acid in 50 ml of water are added tothe organic solution. The biphasic solution is then stirred foradditional 6 hours at 50° C. The layers are separated and 7.1 g ofcitric acid in aqueous solution are added again. The reaction mixture isstirred over night at internal temperature of 50° C. For work up 50 mlof water are added to the reaction solution at room temperature. Theorganic phase is washed with 50 ml of water (2×25 ml) and 50 ml ofNaHCO_(3 [)8%], (2×25 ml). The organic phase is washed to a neutral pHwith 50 ml of water (2×25 ml) and evaporated to yield (VIIIa) as a veryviscous oil.

¹H-NMR (400 MHz, DMSO-d₆): (2 rotamers), 7.52-7.50 (d, 1H), 7.37 (s,1H), 7.04-7.02 (d, 1H), 6.99 (s, 1H), 4.35-4.31 (m, 1H), 4.06-4.04 (t,2H), 3.83 (s, 3H), 3.49-3.46 (m, 3H), 3.25 (s, 3H), 2.51-2.49 (m, 1H),2.05-1.95 (m, 4H), 1.87-1.80 (m, 2H), 1.63-1.58 (t, 1H), 1.25 (s, 9H),0.97-0.95 (d, 3H), 0.92-0.91 (d, 3H), 0.86-0.84 (d, 3H), 0.83-0.81 (d,3H), 0.80-0.78 (d, 3H).

MS: [MH−Boc]H⁺=450

R_(f)=0.45 (heptane:EtOAc=1:1)

5a) Purification of Compound (VIIIa) Via Salt Formation to GiveCrystalline Li-Salt (VIIIa′)

30 g (55 mmol) of crude compound (VIIIa) are dissolved in 120 ml ofethanol to give a clear solution. The solution is cooled to 0° C. and110 mmol LiOH (2.65 g in 100 ml water) is slowly added under stirringduring 45 minutes. The reaction is slightly exotherm. After 2 hours aHPLC control shows complete conversion of starting material to thehydroxyl acid Li compound (VIIIa′). The slightly yellow, turbid solutionis partially evaporated by distillation of ca. 100 ml of ethanol-watermixture. The residual concentrated water solution of the Li-salt isextracted twice with ethyl acetate (2×100 ml). The combined ethylacetate phases which now contain the Li salt (XII) is back extractedwith 50 ml saturated sodium chloride solution. The organic phase is thenevaporated in vacuum to give 33.0 g of a foam which is dissolved in 30ml of diisopropylether. To this solution is added at 0° C. 60 ml ofn-heptane (isomer mix.). The mixture is seeded and put in therefrigerator over night. The formed crystalline material is filtered andwashed with 2 portions (2×30 ml) of cold n-heptane and dried in thevacuum oven over night to obtain a white, crystalline powder.

m.p.: 62-70° C. (melting range)

MS: [M-Li]=566; Li-salt: MH⁺:574

¹H-NMR (600 MHz, DMSO-d₆): at room temp. rotamer mix (ca. 1:3): 7.58 (d,min.), 7.5 (d, maj.), 7.43 (br. s, min.), 7.38 (br. s., maj.), 7.05 (d,min.), 6.98 (d, maj.), 6.1 (br. d, —OH, min.+maj.), 4.03 (br. m.,—OCH₂), 3.82 (s, —OCH₃), 3.5-3.35 (br. m., —OCH₂, +H₂O), 3.22 (s,—OCH₃), 3.05 (br. m, 1H), 2.0-1.9 (br. m, 3H), 1.85-1.7 (br. m, 3H),1.65-1.55 (br. m, 1H), 1.4-1.3 (br. m, 4H), 1.28 (Boc, maj.), 0.95 (Boc,min.), 0.85-0.72 (m, 12H+heptane).

at 300° Kelvin: 7.52 (br. d, 1H), 7.45 (br. d, 1H), 7.0 (2d, 1H)

IR: 3350 (br, NH, OH), 2960, 2932, 2873 (s, as CH_(n)), 1686 (C═O), 1581(as —COO⁻), 1515 (amide, arom.), 1428 (sy. COO⁻), 1267 (C—O), 1174(C—O-Boc), [cm⁻¹].

5b) Reaction of Boc-Lactam-Lactone (VIa) Via Aryl-Alkyl-Mg-Species(VIIb) to Compound (VIIIa)

A dry flask, (No. 1, 100 ml) is charged with 15 ml of dried THF which isthen cooled to 0° C. under argon. When the temperature reached 0° C.,6.25 ml of an isopropyl magnesium chloride solution (2.0 molar, inTHF=12.5 mmol) is added. Then 7.5 ml of a n-butyl lithium solution (1.6molar in n-hexane=12.5 mmol) are added via syringe during 10 minutes.The reaction mixture is stirred at 20-25° C. for 30 minutes. After thattime a solution of compound (VII′), X═Br, 2.75 g (10 mmol) in 7.5 ml ofdry THF is dropped to the reaction mixture during 15 min. at 25° C.,which is slightly exotherm with gas evolution. The dropping funnel isrinsed with 2 ml of THF and the reaction mixture is then stirred at 25°C. for at least 3 hours, followed by a HPLC analysis to check theconversion of VII′. —In a second flask (No. 2) 3.53 g (10 mmol) ofcompound (VIa) is charged together with 22.5 ml of dry THF under argon.The solution is then cooled to −10° C. To the suspension of (VIa) inflask No. 2 is added the aryl alkyl species (VIIb) via a Teflon tubeduring a time periode of 1-2 hours under argon pressure. The reactionmixture is then stirred at −10° C. for additional 15 hours.

After HPLC analysis showed complete conversion of (VIa) the reactionmixture is quenched onto a solvent mixture of 25 ml of tBME and 22 ml ofwater containing 3.2 ml of acetic acid under vigorous stirring at 0° C.during 30 min. Then the aqueous phase is separated and the organic phaseis extracted three times with 15 ml of water (total 45 ml). The organicphase is then evaporated in vacuum to an oily residue. The residue isagain dissolved in 35 ml of ethanol and treated at 0° C. with an aqueoussolution of 0.48 g of lithium hydroxide in 20 ml of water under stirringfor 5 hours to give the lithium salt (VIIIa′). The reaction mixture isthen concentrated in vacuum to remove most of the ethanol and is thendiluted with 35 ml of water and 20 ml of TBME and is stirred for 5minutes. The organic phase is separated and the aqueous phase is againextracted with 20 ml of TBME. The combined organic phases contain theunwanted lipophilic aromatic side products, while the aqueous phasecontains the desired lithium salt (VIIIa). The basic aqueous phase isneutralized by addition of 5.3 g of solid citric acid under stirringfollowed by the addition of 40 ml of ethyl acetate. The neutralizedaqueous phase is separated and replaced by 3.2 g of additional citricacid dissolved in 30 ml of water. The reaction mixture is thenvigorously stirred for 2 hours at 65° C. to achieve lactonisation. AfterHPLC control shows complete lactonisation 45 ml of saturated sodiumbicarbonate solution is added slowly under stirring. Stirring is stoppedand the aqueous phase is removed while the organic phase, which containsthe product (VIIIa) is again washed twice with 25 ml of water (total 50ml). Finally the organic phase is evaporated in vacuum to give a verysticky viscous residue (VIIIa) which is pure according to HPLC analysis.

5c) Reaction of Boc-Lactam-Lactone (VIa) and Aryl-Li-Species (VIIa) ViaCompound (VIIIa′) to Compound (Xa) by Sodium Borohydride Reductionwithout Going Via (VIIIa)

A 750 ml three necked flask was dried under argon flow by heating to150° C. After cooling down under argon to room temperature the flask ischarged with 25 g of bromide (90.8 mmol). The solid is then dissolved byadding 440 ml of dry (mol sieve) tetrahydrofurane. This solution is thencooled down to −78° C. At this temperature a solution of n-butyllithium(1.6 molar) in n-hexane (57 ml) is added slowly over 30 minutes to givea clear, colourless solution. The reaction mixture is kept at thistemperature vor 1 hour. After that time a HPLC control showed completehalogen-metalation exchange together with ca. 10-15% of homo couplingproduct.

In a second flask 26.73 g (75.6 mmol) of Boc-compound (VIa) dissolved in440 ml of dry THF (over mol sieve) is cooled down to −70° C. To thissolution is added under argon pressure the Li-species (VIIa) from flask1 within 15 minutes to give an almost colourless clear solution. After20 minutes an HPLC control showed complete con-version of (VIa). Thereaction mixture is quenched onto a biphasic mixture of 600 ml aqueouscitric acid solution (10%) and 500 ml of TBME at 0° C. under vigorousstirring.

The aqueous phase is extracted with 250 ml of TBME. The combined organicphases twice with (2×200 ml) aqueous citric acid, then twice (2×200 ml)sodium bicarbonate (10%) and finally with 2×200 ml of water. The organicphase is dried over MgSO₄ and evaporated in vacuum to give a thick oil.

Then this oil (48.6 g) is dissolved in 500 ml of ethanol to give acolourless solution. To this solution is added at 0° C. 151 ml of a 1molar solution of lithium hydroxide (0.151 mol) under stirring. Thereaction mixture is slowly warmed up to room temperature and after 2hours lactone ring opening was complete (HPLC) to give the lithium salt(VIIIa′).

To this solution are added at 40° C. small portions of sodiumborohydride are added (3.8 g, 100 mmol) over a period of 2 hours. HPLCcontrol showed after 5 hours 66% conversion of starting material.Additional 756 mg, (20 mmol) of NaBH₄ is added and stirring at 40° C. iscontinued over night. A HPLC analysis showed complete con-version to theepimeric mixture of (Xa′). The reaction mixture was cooled to 0° C. andexcess of borohydride was destroyed by slowly adding 400 ml of aqueouscitric acid solution (˜10%) at 0° C. under stirring to get pH 3. Stronghydrogen gas evolution is observed. The reaction mixture is concentratedin vacuum to remove ethanol. The aqueous phase is extracted with ethylacetate and the ethylacetate phase is again mixed with 300 ml of anaqueous solution of citric acid and then warmed up to 50-60° C. for 12hours whereby lactonisation takes place to give the 2 epimeric alcohols(Xa) after phase separation and evaporation as a thick oil which wascrystallized from TBME/heptane mixture to give a white crystalline solidin the ratio of 95:5. Spectroscopic data are in accordance with (Xa)epimeric mixtures.

6) Preparation of Compound (IX), (Penultimate Precursor) by DirectHydrogenation of Compound (VIIIa)

2.75 g (5 mmol) of compound (VIIIa) are dissolved in 30 ml of a mixtureof ethanol:acetic:acid (2:1) and 0.35 g of catalyst Pd—C (10%),Engelhard 4505 is added. The hydrogenation is performed at 50° C. and 5bar pressure. After 10 h a sample shows uncomplete conversion. Anadditional amount of catalyst (0.35 g) is added and hydrogenation iscontinued. After 46 hours almost all starting material is converted. Thereaction mixture is filtered and washed with ethanol and the filtrate isevaporated in vacuum to give an almost colourless oil. The crude productmixture was dissolved in toluene and was washed 3-times with 25 ml ofsaturated NaHCO₃-solution to neutralize the acetic acid and extract itto the aqueous phase. After evaporation of the toluene in vacuum analmost colourless viscous oil was obtained (2.21 g). The tlc (SiO₂,heptane:ethyl acetate (1:1) of this mixture showed 4 different spotsbesides small amounts of starting material (VIII, R_(f) 0.45) which werevisualized by spraying with Dragendorf's reagent. The spot on the topwith R_(f)=0.60 was the desired compound (IXa). The two spots with R_(f)0.33 and 0.40 are the 2 different epimers of the alcohol derivative(Xa). The spot with R_(f) 0.55 is compound (XI) which is formed fromepimeric compounds (Xa) with R_(f) 0.33 and 0.40 under acidic conditions(AcOH) at higher temperature or with ion exchange resin at roomtemperature. Similar behaviours could be observed in HPLC.

After preparative column chromatography of the 2.21 g of the crudemixture 20 pure fractions of the desired compound (IXa), R_(f)=0.60,could be collected which crystallized directly from the oil. Thecrystalline material was recrystallized from heptane.

Compound (IXa):

M.p: 78-79° C.

¹H-NMR (400 MHz, CDCl₃): 0.74-0.76 (2×d, 6H), 0.85-0.87 (d, 3H),0.92-0.94 (d, 3H), 1.16-1.23 (bm, 1H), 1.38, (s, 9H, Boc), 1.5-1.65(br-m, 2H), 1.95-2.15 (br-m, 5H), 2.50-2.35 (br-m, 1H), 2.45-2.52 (brm,1H), 2.50-2.59 (brm, 1H), 3.28 (s, 3H), 3.50 (t, 2H), 3.70-3.80 (s+m,4H), 4.03 (t, 2H), 4.28-4.35 (m, 2H), 6.62 (d, 1H), 6.67 (s, 1H), 6.69(d, 1H).

IR: 3358 (—NH), 1773 (lacton), 1705 (carbamat), 1518 (amide II) cm⁻¹;

(FTIR-microskop in transmission)

MS: MH⁺=535.7

Also the other “spots” are isolated and characterized by spectroscopicdata:

Spot at R_(f)=0.55 corresponds to compound (XIa)

¹H-NMR (400 MHz, CDCl₃): 0.77-0.79 (d, 3H), 0.86-0.88 (d, 3H), 0.88-0.90(d, 3H), 0.97-0.99 (d, 3H), 1.10-1.30 (br-peak, 9H, boc), 1.78-1.86 (m,1H), 2.0-2.06 (m, 2H), 2.08-2.16 (brm, 3H), 2.50-2.60 (brm, 1H), 3.27(s, 3H), 3.50 (t, 2H), 3.77 (s, 3H), 4.0-4.10 (brm, 3H), 4.20-4.40(br-peak, 2H), 6.72-6.74 (d, 1H), 6.75-6.77 (d, 1H), 6.83 (s, 1H).

m.p.: 63-69° C.

IR: 3057, 2970, 1773 (lacton), 1688 (Boc), 1515, 1390, 1368 [cm-1]

MS: MH⁺=534; M-NH₄ ⁺=551

Spot at R_(f)=0.40 corresponds to compound (Xa)-epimer 1 (syn-epimeraccording to X-ray structure analysis:

¹H-NMR (400 MHz, CDCl₃): 0.82-0.88 (3×d, 9H), 0.92-0.94 (d, 3H), 1.40(s, 9H), 1.80-1.93 (brm, 2H), 2.03-2.11 (brm, 4H), 2.37-2.45 (brm, 1H),3.32 (s, 3H), 3.35 (t, 2H), 3.83 (s, 3H), 4.05-4.20 (brm, 3H), 4.25 (d,1H), 4.60 (d, 1H), 6.80 (d, 1H), 4.83 (dd, 1H), 6.95 (s, 1H).

MS: M+NH₄ ⁺=569; M-H=550

7) Preparation of Compound (IXa), by Direct Hydrogenation of Compound(VIIIa) in EtOH

H₂O (9:1 at normal pressure & room temperature with Pd—C, 10%, wet,JM-type39:

5.5 g (10 mmol) of compound (VIIIa) was dissolved in of a mixture of 90ml ethanol and 10 ml water. To the mixture is added 5 g of catalyst Pd—C(10%), water cont. ca. 50%, from Johnson Matthey, typ 39. The mixture isstirred at room temperature and normal pressure for 20 hours. After thattime the conversion of compound (VIIIa) was 98% and 66% of the desiredcompound (IXa) was formed together with 28% of epimeric alcohols (Xa)and 4% pyrrolidine lactone (XIa). Hydrogenation under the sameconditions was continued for another 48 hours without additionalcatalyst. After that time the catalyst was filtered off and the solventwas evaporated under reduced pressure to afford an oil (5.9 g) whichcontained according to HPLC 89% of compound (IXa) and each 5% compound(XIa) and starting material (VIIIa). The oil was treated and stirred at0° C. with 10 ml of n-heptane (isomer mix) and seeded with a smallamount of compound (IXa) upon the product started to crystallize. Theflask was stored in the refrigerator over night and for another 24 hoursat −18° C. The product was filtered and washed with small volumes ofvery cold n-heptane to give after drying in vacuum the desired product,which was pure by HPLC, TLC and ¹H-NMR.

8) Preparation of Compound (Xa), (Syn-Anti Epimeric Alcohols) byHydrogenation of Compound (VIIIa) in EtOAc at 6 Bar, 20-60° C. withCatalyst Pd—C, 10%, in the Presence of Potassium Formate

22.0 g (40 mmol) of compound (VIIIa) as an oil are dissolved in 150 mlof ethyl acetate. 10 g of Pd/C (10%), type Engelhard 4505, and 500 mg ofpotassium formate was added to buffer acidic components of the catalyst.Hydrogenation was performed with 6 bar and room temperature at thebeginning and was later increased to 60° C. After 8 days additionalcatalyst (5 g) was added and after 9 days the conversion was 91% and the2 epimeric alcohols were formed in a ratio of 93:7 (syn: anti)exclusively without any further hydrogenolysis to compound (IXa) orformation of compound (XIa). The catalyst was filtered off and thesolvent was evaporated in vacuum to give an oil which crystallizedduring standing at room temperature (19.0 g). This material wasre-crystallized from tert.-butyl methylether (20 ml) and n-heptane (60ml, iso mixture) at 20° C. and seeding. After crystallization is almostcomplete (2 h) additional 40 ml of n-heptane is added at 20° C. understirring for 2 hours to give then after storage in the refrigerator overnight and filtration, washing with cold n-heptane and drying the whitecrystalline material (syn/anti ratio=93:7, HPLC).

m.p. of the syn/anti alcohol mixture: 69-71° C.

8) Preparation of Compound (Xa′), (Salt of Hydroxy Acid from Syn-AntiEpimeric Alcohol (Xa)

1 g (1.8 mmol) of an epimeric mixture of crystalline alcohols (Xa),(ratio ca. 9:1) is dissolved in 10 ml of ethanol. The solution is cooledto 0° C. and a solution of lithium hydroxide (3.6 mmol) in water (4 ml)is added under stirring. After stirring at ambient temperature for 2hours the reaction is complete. Most of the ethanol is removed bydistillation and the residual aqueous phase is extracted with 2×20 ml ofethyl acetate. The combined ethyl acetate extracts are washed with 5 mlof brine and is then evaporated to an oily solid. To this is added 5 mlof n-heptane to crystallize the material. The crystalline suspension isstored over night in the refrigerator and is then filtered and washedwith cold n-heptane and dried in vacuum to give a white solid.

m.p.: 118-128° C. (melting range)

MS: [M-Li]⁻=568; MH⁺=576

IR: FTIR microscope i. transmission: 3440, 3355, 3167 (br, NH, OH);2958, 2874 (aliph. —CH), 1686 (C═O, Boc), 1605 (as, COO⁻), 1555(amide-II), 1514, 1438 (sy, COO⁻), 1367, 1258, 1171, 1028, [cm⁻¹]

9) Preparation of Compound (IXa′), Li-Salt of Hydroxy Acid from (IXa)

1 g (1.86 mmol) of crystalline compound (IXa) was dissolved in 10 ml ofethanol. To this solution was added a solution of 88.6 mg (3.7 mmol) oflithium hydroxide in 5 ml of water. The homogeneous reaction mixture wasstirred at room temperature for 2 hours. HPLC showed after that timecomplete conversion. The solution was evaporated in vacuum to removemost of the ethanol. The aqueous phase was extracted with 2×20 ml ofethyl acetate. The combined ethyl acetate phases are washed with 5 ml ofbrine and are then evaporated to give a sticky solid. To this is added10 ml of n-heptane under stirring at 0° C. to crystallize the material.The crystalline suspension is stored over night in the refrigerator andis then filtered and washed with cold n-heptane and dried in vacuum togive a white solid.

m.p.: 88-98° C. (melting range)

IR: FTIR-microscope in transmission: 3573 (—OH), 3377 (—NH), 2955, 2933,2871, 1679 (Boc), 1572 (COO⁻), 1514 (amide-II), 1439, 1423 (COO⁻), 1366,1260, 1239, 1170, 1122, 1026 [cm⁻¹]

MS: [M-Li]⁻=552; MH⁺=560

10) Hydrogenation of Compound (VIIIa′), (Salt of Hydroxy Acid from(VIIIa)) with Pd—C to Compound (Xa′) as Epimeric Mixture

2.8 g of (5.0 mmol) of carboxy-Li-salt (compound VIIIa′) was dissolvedin 40 ml of isopropanol. 2.5 g of Pd—C (10%), JM type 39, wet, was addedand hydrogenated at 25° C. over night (17 h) at 0.2 bar. After that timeconversion of compound (VIIIa′) was 86% (HPLC). Temperature wasincreased to 50° C. and hydrogenation was continued for additional 24hours. After 41 hours only small changes in conversion were observed butthe ratio of syn/anti epimeric alcohols has changed from 83% syn/17%anti to 67% syn/33% anti. Therefor additional catalyst (1 g) was addedand hydrogenation was continued at 50° C. for additional 6 hours. Afterthat time HPLC analysis showed no further conversion but again a changein the syn/anti ration to 62:38. Hydrogenation was continued at 50° C.for additional 36 hours without additional catalyst loading. After thattime HPLC analysis showed a syn/anti ratio of 45:55, but no furtherchange in conversion (83%) of starting material. This shows aninterconversion of the syn epimeric alcohol to the anti epimer under thereaction conditions by an oxidative-reductive cycle. Hydrogenation wasstopped, the catalyst was filtered off and the solvent was evaporated toa semi-solid oil.

11) Reduction of Li-Salt (VIIIa′) with Sodium borohydride via (Xa)′ to(Xa) Using Sodium Borohydride Reduction in Ethanol-Water (1:1):

2.3 g (4 mmol) of Li-salt (VIIIa′) is dissolved at room temperature in amixture of 10 ml of water and 10 ml of ethanol. The solution is warmedup to 40° C. and small portions of sodium borohydride are added (151 mg,4 mmol) over a period of 1 hour. HPLC control showed after 4 hours 66%conversion of starting material. Additional 38 mg, (1 mmol) of NaBH₄ isadded and stirring at 40° C. is continued over night. HPLC analysisshowed complete conversion. Excess of borohydride was destroyed byquenching on 40 ml of aqueous citric acid solution (10%) to get pH 3.The reaction mixture is concentrated in vacuum to remove ethanol. Theaqueous phase is extracted with ethyl acetate and the ethylacetate phaseis again mixed with 10 ml of an aqueous solution of citric acid and thenwarmed up to 50-60° C. for 2 hours whereas lactoni-sation takes place togive the 2 epimeric alcohols (Xa) after phase separation and evaporationas a an sticky oil which crystallized from TBME/heptane as a white solidin the ratio of 95:5. HPLC and spectroscopic data are in accordance withother samples of (Xa) mixtures.

Other solvent mixtures like THF/water, or i-propanol/water or wateralone or ethanol with 20 vol. % of water are also good solvents for thisborohydride reduction.

12) Barton-McCombie-Route to Compound (IXa) a) Preparation of compound(XVa)=Imidazole-1-carbothioic acidO—{(S)-2-[(S)-2-tert-butoxycarbonylamino-2-((2S,4S)-4-isopropyl-5-oxo-tetrahydro-furan-2-yl)-ethyl]-1-[4-methoxy-3-(3-methoxy-propoxy)-phenyl]-3-methyl-butyl}ester

Epimeric compound (Xa) (1.66 g, 3 mmole) is dissolved in toluene (18 mL)and 1,1-thiocarbonyl-diimidazole (0.804 g, 4.5 mmole) is added, followedby the addition of dimethylaminopyridine (0.037 g). The reaction mixtureis stirred over night at room temperature. For work-up, aqueous,saturated NaHCO3 (20 mL) is added and the layers are separated. Theorganic layer is extracted with aq., sat. NaHCO3 (20 mL) and with water(20 mL). The organic layer is dried on anhydrous MgSO4 and the solventis evaporated under reduced pressure to obtain 2.08 g crude product as aviscous liquid. The crude product was purified by flash-chromatographyon silica gel with t-butyl-methyl ether as mobile phase to obtain purecompound (XVa) as a white foam. 1H-NMR, IR and HR-MS Spectra of theproduct confirmed the proposed structure as a mixture ofdiastereoisomers (epimers). The ¹H-NMR spectrum was complicated by thepresence of rotamers. ¹H-NMR (400 MHz, 354K, d₆-DMSO): 0.65-0.99 (m,12H), 1.42 (s, 9H), 1.44-2.44 (m, 10H), 3.24 (s, 3H), 3.47 (t, 2H), 3.75(s, 3H), 3.76-3.90 (m, 1H), 4.01 (t, 2H), 4.06-4.40 (m, 1H), 4.73-4.89(m, 1H), 6.81-7.03 (m, 3H), 7.05 (broad s, 1H), 7.62 (broad s, 1H), 8.28(broad s, 1H). FT-IR (in transmission): 3317, 3125, 2961, 2933, 2875,2836, 1769, 1701, 1604, 1591, 1517, 1469, 1427, 1390, 1366, 1331, 1290,1265, 1221, 1168, 1143, 1120, 1097, 1064, 1046, 1026, 968, 949, 886,811, 753, 725, 694, 666, 646 cm⁻¹. HR-MS: C₃₄H₅₁N₃O₈S. Calculated forMNa⁺=684.32891 found: 684.32894; Calculated for MK⁺=700.30284, found:700.30306.

b) Preparation of Compound (IXa) by Reduction of Compound (XVa) withTributyltin Hydride

Compound (XVa) (=Imidazole-1-carbothioic acidO—{(S)-2-[(S)-2-tert-butoxycarbonylamino-2-((2S,4S)-4-isopropyl-5-oxo-tetrahydro-furan-2-yl)-ethyl]-1-[4-methoxy-3-(3-methoxypropoxy)-phenyl]-3-methyl-butyl}ester)(0.4 g, 0.604 mmole) is dissolved in toluene (8 mL). The solution isheated to 100° C. Tributyltin hydride (0.916 g is added via a syringe atthis temperature, followed by the addition of a solution of AIBN(0.01984 g) in tetrahydrofuran (0.4 mL). The reaction mixture is stirredfor 1 hour at 100° C., after which time another portion of AIBN (0.01984g) in tetrahydrofuran (0.4 mL) is added. Stirring was continued for oneadditional hour at 100° C. and the reaction was quenched by addition ofthe reaction mixture onto cold methanol (10 mL) at −20° C. Toluene (10mL) is added and the mixture is extracted with aqueous 1N HCl (2×10 mL)and with water (10 mL). The aqueous layers are combined and areextracted with toluene (10 mL). The organic layers are combined, driedon anhydrous Na₂SO₄ and the solvent was evaporated under reducedpressure. The oily crude product was purified by flash-chromatography onsilica gel with hexane fraction/isopropanol (9:1) to obtain compound(IXa). The product was identical to a reference sample of compound IXaaccording to HPLC and 1H-NMR.

c) Preparation of Compound (IXa) by Reduction of Compound (XVa) withtris(trimethylsilyl)silane

Compound (XVa) (=Imidazole-1-carbothioic acidO—{(S)-2-[(S)-2-tert-butoxycarbonylamino-2-((2S,4S)-4-isopropyl-5-oxo-tetrahydro-furan-2-yl)-ethyl]-1-[4-methoxy-3-(3-methoxypropoxy)-phenyl]-3-methyl-butyl}ester)(0.4 g, 0.604 mmole) is dissolved in a mixture of toluene (4 mL) andtert-dodecylmercaptane (4 mL). The solution is heated to 100° C.

Tris(trimethylsilyl)silane (774.5 mg, 3 mmole) is added, followed by theaddition of a solution of AIBN (20 mg) in toluene (0.4 mL). The reactionmixture is stirred for 15 minutes at 100° C. and is poured onto coldmethanol (10 mL) at −20° C. to quench the reaction. Toluene (10 mL) isadded and the mixture is extracted with aqueous 1N HCl (2×10 mL) andwater with (10 mL). The aqueous layers are combined and extracted withtoluene (10 mL). The organic layers are combined, dried over anhydroussodium sulphate and the solvent is evaporated. The crude product waspurified by flash chromatography on silica gel to obtain pure compound 4(30 mg, 18.5% yield). The product was identical to a reference sample ofcompound IXa according to HPLC and 1H-NMR.

13) Synthesis of Bis-pseudoephedrine Precursor (Ia′vi) from(+)-(1S,2S)-pseudo-ephedrine as Auxiliary: according to Lit.: A. Myerset al., J.A.C.S., 119, 6496 (1997)

A 100 ml three necked flask was dried under argon flow by heating to150° C. After cooling down under argon to room temperature, 2.54 g (60mmol) of dried lithium chloride was added. Then 3.15 ml ofdiisopropylamine dis-solved in 12 ml of dry THF is added under stirring.The resulting suspension is cooled to −78° C. under argon. To thissuspension is added under stirring at −78° C. via syringe 13 ml of a 1.6molar solution of butyl lithium in hexane to give LDA. After stirringthe suspension for further 15 minutes, a solution of 2.5 g ofN-isovaleroyl-(S,S)-pseudo-ephedrine (10 mmol) dissolved in 10 ml of THFis added via syringe at −78° C. Then the suspension is warmed up to 0°C. within 30 min. At this temperature a solution of 1.18 g (5.5 mmol) oftrans-1,4-dibromo-2-butene in 5 ml of THF is added via syringe. Stirringis continued at 0-5° C. for further 30 min. After stirring the reactionmixture at room temperature over night a HPLC control showed completeconversion. The reaction mixture is quenched onto a mixture of 80 ml ofaqueous ammonium chloride solution and 50 ml of TBME. The aqueous phaseis extracted twice with 25 ml of TBME. Then the combined organic phasesare washed with brine (50 ml) dried over MgSO₄ and are finally filteredand evaporated in vacuum to give a very viscous oil which results in awhite foam after evacuation in high vacuum. MS, ¹H-NMR in d₆-DMSO atroom temperature (300° K) and at elevated temperature (394° K) confirmthe structure. The compound exists at RT as a mixture of 2 rotamers inthe ratio (˜2:1).

MS: 551 (MH⁺)

IR: 3350 (br, OH), 2960, 1608 (amid), 1450, 1407, 1030, 970, 755, 700[cm⁻¹]

¹H-NMR, 600 MHz (d₆-DMSO): complex spectrum, 2 sets of signals, at 300°K (mixture of rotamers (˜2:1)

1-16. (canceled)
 17. A method for preparing a compound of formula (VIII)

wherein R³ and R⁴ are as defined for a compound of formula (II) and Actis an activating group selected from an amino protecting group, inparticular a carbamate, R¹ is halogen, hydroxyl, C₁₋₆halogenalkyl,C₁₋₆alkoxy-C₁₋₆alkyloxy or C₁₋₆alkoxy-C₁₋₆alkyl; R² is halogen,hydroxyl, C₁₋₄alkyl or C₁₋₄alkoxy, or a salt thereof; comprising thestep of lactam ring opening of the N-activated lactam lactone of formula(VI) or a salt thereof defined above with a compound of formula (VII)

wherein Y is a metal containing group such as —Li, —MgX, -magnesate,aryl magnesium species, alkyl magnesium species, —MnX, (alkyl)₃MnLi—, or—CeX₂ wherein X is halogen such as Cl, I or Br, more preferably Br; andR¹ and R² are as defined for a compound of formula (VIII).
 18. Themethod according to claim 17 wherein the N-activated lactam lactone offormula (VI) is reacted with a compound of the following formula:


19. A compound of formula (VII)

wherein Y is a metal containing group such as —Li, —MgX, -magnesate,aryl magnesium species such as

wherein R¹ and R² are as defined herein, alkyl magnesium species, suchas branched C₁₋₇alkyl-Mg—, —MnX, (alkyl)₃MnLi—, or —CeX₂ wherein X ishalogen such as Cl, I or Br, more preferably Br, R¹ is halogen,hydroxyl, C₁₋₆halogenalkyl, C₁₋₆alkoxy-C₁₋₆alkyloxy orC₁₋₆alkoxy-C₁₋₆alkyl; and R² is halogen, hydroxyl, C₁₋₄alkyl orC₁₋₄alkoxy; or a salt thereof.
 20. The compound according to claim 19wherein Y is MgBr, a magnesate or Li.
 21. The compound according toclaim 19, having the following formula:


22. A compound of formula (VIII)

wherein R³ is C₁₋₇alkyl or C₃₋₈cycloalkyl; R⁴ is C₁₋₇alkyl, C₂₋₇alkenyl,C₃₋₈cycloalkyl, phenyl- or naphthyl-C₁₋₄alkyl each unsubstituted ormono-, di- or tri-substituted by C₁₋₄alkyl, O—C₁₋₄alkyl, OH,C₁₋₄alkylamino, di-C₁₋₄alkylamino, halogen and/or by trifluoromethyl; R¹is halogen, hydroxyl, C₁₋₆halogenalkyl, C₁₋₆alkoxy-C₁₋₆alkyloxy orC₁₋₆alkoxy-C₁₋₆alkyl; R² is halogen, hydroxyl, C₁₋₄alkyl or C₁₋₄alkoxy;and Act is an activating group selected from an amino protecting group,in particular a carbamate; or a salt thereof.
 23. The compound accordingto claim 22, having the formula


24. The compound according to claim 22, having the formula


25. A compound of formula (VIII′)

wherein R³ is C₁₋₇alkyl or C₃₋₈cycloalkyl; R⁴ is C₁₋₇alkyl, C₂₋₇alkenyl,C₃₋₈cycloalkyl, phenyl- or naphthyl-C₁₋₄alkyl each unsubstituted ormono-, di- or tri-substituted by C₁₋₄alkyl, O—C₁₋₄alkyl, OH,C₁₋₄alkylamino, di-C₁₋₄alkylamino, halogen and/or by trifluoromethyl; R¹is halogen, hydroxyl, C₁₋₆halogenalkyl, C₁₋₆alkoxy-C₁₋₆alkyloxy orC₁₋₆alkoxy-C₁₋₆alkyl; R² is halogen, hydroxyl, C₁₋₄alkyl or C₁₋₄alkoxy;and Act is an activating group selected from an amino protecting group,in particular a carbamate; or a salt thereof.
 26. The compound accordingto claim 25 in the form of a salt.
 27. The compound according to claim25 in the form of the Li, Na, K, Mg, Ca, primary, secondary or tertiaryamine salt.
 28. The compound according claim 25, having the formula

or preferably a salt thereof.
 29. The compound according to claim 25,having the formula

or preferably a salt thereof.
 30. A method for preparing a compound offormula (IX)

wherein R³ and R⁴ are as defined for a compound of formula (II), R¹ andR² are as defined for a compound of formula (VIII) and Act is anactivating group selected from an amino protecting group, in particulara carbamate, or a salt thereof, comprising reduction of the benzyliccarbonyl of the compound of formula (VIII) as defined in claim 22 or acompound of formula (VIII′) as defined in claim 25 to a methylenemoiety.
 31. A method for preparing a compound of formula (X)

wherein R³ and R⁴ are as defined for a compound of formula (II), R¹ andR² are as defined for a compound of formula (VIII) and Act is anactivating group selected from an amino protecting group, in particulara carbamate, or a salt thereof, comprising reduction of the benzyliccarbonyl of the compound of formula (VIII) as defined in claim 22 to ahydroxyl moiety.
 32. A method for preparing a compound of formula (X)

wherein R³ and R⁴ are as defined for a compound of formula (II), R¹ andR² are as defined for a compound of formula (VIII) and Act is anactivating group selected from an amino protecting group, in particulara carbamate, or a salt thereof, comprising as a one-pot synthesis thesteps of lactam ring opening of the N-activated lactam lactone offormula (VI) or a salt thereof as defined in claim 14 with a compound offormula (VII)

wherein Y is a metal containing group such as —Li, —MgX, -magnesates,aryl magnesium species such as

wherein R1 and R2 are as defined herein, alkyl magnesium species, suchas branched C₁₋₇alkyl-Mg—, —MnX, (alkyl)₃MnLi—, or —CeX₂ wherein X ishalogen such as Cl, I or Br, more preferably Br; and R¹ and R² are asdefined for a compound of formula (X), to obtain a compound of formula(VIII′), or a salt thereof, as defined in claim 25, followed byreduction of the benzylic carbonyl group of the compound of formula(VIII′) or a salt thereof to obtain a compound of formula (X′), or asalt thereof, as defined in claims claim 34, and lactonization of thecompound of formula (X′) to obtain a compound of formula (X).
 33. Amethod for preparing a compound of formula (X′)

wherein R³ and R⁴ are as defined for a compound of formula (II), R¹ andR² are as defined for a compound of formula (VIII) and Act is anactivating group selected from an amino protecting group, in particulara carbamate, or a salt thereof, comprising reduction of the benzyliccarbonyl of the compound of formula (VIII′) as defined in claim 25 to ahydroxyl moiety.
 34. A compound of formula (X′)

wherein R³ is C₁₋₇alkyl or C₃₋₈cycloalkyl; R⁴ is C₁₋₇alkyl, C₂₋₇alkenyl,C₃₋₈cycloalkyl, phenyl- or naphthyl-C₁₋₄alkyl each unsubstituted ormono-, di- or tri-substituted by C₁₋₄alkyl, O—C₁₋₄alkyl, OH,C₁₋₄alkylamino, di-C₁₋₄alkylamino, halogen and/or by trifluoromethyl; R¹is halogen, hydroxyl, C₁₋₆halogenalkyl, C₁₋₆alkoxy-C₁₋₆alkyloxy orC₁₋₆alkoxy-C₁₋₆alkyl; R² is halogen, hydroxyl, C₁₋₄alkyl or C₁₋₄alkoxy;and Act is an activating group selected from an amino protecting group,in particular a carbamate; or a salt thereof.
 35. The compound accordingto claim 34 in the form of a salt.
 36. The compound according to claim34 in the form of the Li, Na, K, Mg, Ca, primary, secondary or tertiaryamine salt.
 37. The compound according to claim 34 having the formula

or preferably a salt thereof.
 38. The compound according to claim 34,having the formula

or preferably a salt thereof.
 39. A method for preparing a compound offormula (IX)

wherein R³ and R⁴ are as defined for a compound of formula (II), R¹ andR² are as defined for a compound of formula (VIII) and Act is anactivating group selected from an amino protecting group, in particulara carbamate, or a salt thereof, said method comprising a method forpreparing a compound of formula (X) as set forth in claim 31 or acompound of formula (X′) as set forth in claim 34 and then hydrogenationof the compound of formula (X) or (X′) to a compound of formula (IX).40. A method for preparing a compound of formula (XI)

wherein R³ and R⁴ are as defined for a compound of formula (II), R¹ andR² are as defined for a compound of formula (VIII) and Act is anactivating group selected from an amino protecting group, in particulara carbamate, or a salt thereof, said method comprising cyclisation ofthe benzylic alcohol and the amine moieties of the compound of formula(X) as defined in claim 32 to a pyrrolidine moiety.
 41. A method forpreparing a compound of formula (IX)

wherein R³ and R⁴ are as defined for a compound of formula (II), R¹ andR² are as defined for a compound of formula (VIII) and Act is anactivating group selected from an amino protecting group, in particulara carbamate, or a salt thereof, said method comprising a method forpreparing a compound of formula (XI) as set forth in claim 40 and thenhydrogenation or reduction of the pyrrolidine moiety of the compound offormula (XI) to ring-open and to obtain the methylene moiety in position8.
 42. The method according to claim 41, wherein the compound of formula(XI) is converted to a pyrrolidine salt of formula (XI′) or apyrrolidine free base of formula (XI″)

wherein R³ and R⁴ are as defined for a compound of formula (II), R¹ andR² are as defined for a compound of formula (VIII) and X⁻ is an anionsuch as halide, trifluoroacetate, sulfate, nitrate, oxalate, sulfonate,triflate, phosphonate or phosphate.
 43. A compound of formula (XI′):

wherein R³ is C₁₋₇alkyl or C₃₋₈cycloalkyl; R⁴ is C₁₋₇alkyl, C₂₋₇alkenyl,C₃₋₈cycloalkyl, pheny-l or naphthyl-C₁₋₄alkyl each unsubstituted ormono-, di- or tri-substituted by C₁₋₄alkyl, O—C₁₋₄alkyl, OH,C₁₋₄alkylamino, di-C₁₋₄alkylamino, halogen and/or by trifluoromethyl; R¹is halogen, hydroxyl, C₁₋₆halogenalkyl, C₁₋₆alkoxy-C₁₋₆alkyloxy orC₁₋₆alkoxy-C₁₋₆alkyl; R² is halogen, hydroxyl, C₁₋₄alkyl or C₁₋₄alkoxy,and X⁻ is an anion such as halide, trifluoroacetate, sulfate, nitrate,oxalate, sulfonate, triflate, phosphonate or phosphate.
 44. The compoundaccording to claim 43, having the formula


45. The compound according to claim 43, having the formula


46. A compound of formula (IX′)

wherein R³ is C₁₋₇alkyl or C₃₋₈cycloalkyl; R⁴ is C₁₋₇alkyl, C₂₋₇alkenyl,C₃₋₈cycloalkyl, phenyl- or naphthyl-C₁₋₄alkyl each unsubstituted ormono-, di- or tri-substituted by C₁₋₄alkyl, O—C₁₋₄alkyl, OH,C₁₋₄alkylamino, di-C₁₋₄alkylamino, halogen and/or by trifluoromethyl; R¹is halogen, hydroxyl, C₁₋₆halogenalkyl, C₁₋₆alkoxy-C₁₋₆alkyloxy orC₁₋₆alkoxy-C₁₋₆alkyl; R² is halogen, hydroxyl, C₁₋₄alkyl or C₁₋₄alkoxy;and Act is an activating group selected from an amino protecting group,in particular a carbamate; or a salt thereof.
 47. The compound accordingto claim 46 in the form of a salt.
 48. The compound according to claim46 in the form of the Li, Na, K, Mg, Ca, primary, secondary or tertiaryamine salt.
 49. The compound according to claim 46 having the formula

or preferably a salt thereof.
 50. The compound according to claim 46,having the formula

or preferably a salt thereof.
 51. A method for preparing a compound offormula (IX)

wherein R³ and R⁴ are as defined for a compound of formula (II), R¹ andR² are as defined for a compound of formula (VIII) and Act is anactivating group selected from an amino protecting group, in particulara carbamate, or a salt thereof, said method comprising the preparation acompound of formula (X″)

wherein R³ and R⁴ are as defined for a compound of formula (II), R¹ andR² are as defined for a compound of formula (VIII), Act is an activatinggroup selected from an amino protecting group, in particular acarbamate, and Act″ is an electron-withdrawing group, or a salt thereof,by conversion of the benzylic alcohol of the compound of formula (X) isdefined in claim 32 to an activated alcohol moiety.
 52. The methodaccording to claim 50, said method comprising hydrogenation or reductionof the activated alcohol moiety of the compound of formula (X″) asdefined in claim 49 to obtain the methylene moiety in position
 8. 53.The method according to claim 50, wherein Act″ is —(C═O)—R⁹, where R⁹can be substituted alkyl, alkyl-oxy-R¹⁰, substituted aralkyl,substituted aryl, substituted or unsubstituted O-alkyl, substitutedO-aryl, NH—R¹⁰, where R¹⁰ can be substituted alkyl, substituted aryl,substituted aralkyl, such as substituted benzyl, benzoyl, substitutedsulfonyl, wherein the substituent is in each case one or moreelecton-withdrawing moiety such as F or CF₃.
 54. A method for preparinga compound of formula (IX)

wherein R³ and R⁴ are as defined for a compound of formula (II), R¹ andR² are as defined for a compound of formula (VIII) and Act is anactivating group selected from an amino protecting group, in particulara carbamate, or a salt thereof, said method comprising thetransformation of the compound of formula (X) as defined in claim 32 toa thiocarbonyl derivative and subsequently subjecting same toradical-based reduction to obtain the compound of formula (IX).
 55. Themethod according to claim 53, wherein the thiocarbonyl derivative isselected from the group consisting of thionocarbamates, such asimidazolyl derivatives, thiocarbonyls, such as xanthates, andthionocarbonates.
 57. The method according to claim 53 wherein thethiocarbonyl derivative is a thionocabamate of formula (XV)

wherein R³ and R⁴ are as defined for a compound of formula (II) and Actis an activating group selected from an amino protecting group, inparticular a carbamate, R¹ is halogen, hydroxyl, C₁₋₆halogenalkyl,C₁₋₆alkoxy-C₁₋₆alkyloxy or C₁₋₆alkoxy-C₁₋₆alkyl; R² is halogen,hydroxyl, C₁₋₄alkyl or C₁₋₄alkoxy, or a salt thereof.
 57. The methodaccording to claim 53, wherein the thiocarbonyl derivative is reactedwith Bu₃SnH or tris(trimethylsilyl)-silane.
 58. A method for preparing acompound of formula (XII)

wherein R³ and R⁴ are as defined for a compound of formula (II), R¹ andR² are as defined for a compound of formula (VIII) and Act is anactivating group selected from an amino protecting group, in particulara carbamate, or a salt thereof, comprising reacting a compound of theformula IX as defined in claim 30 or a compound of formula (IX′)according to claim 46, or a salt thereof, with an amine of the formulaXIII,

(wherein the amido nitrogen can also be protected if desired and theprotecting group then be removed in the corresponding protected compoundof the formula XII), or a salt thereof.
 59. A method for preparing acompound of formula (XIV)

wherein R³ and R⁴ are as defined for a compound of formula (II), R¹ andR² are as defined for a compound of formula (VIII), or a salt thereof,comprising one or more of the following steps either individually or inany combination: the manufacture of a compound of the formula VIIIaccording to claim 17, or a salt thereof, and the manufacture of acompound of the formula IX according to claim 30, or a salt thereof. 60.A method according to claim 58 comprising the steps of the manufactureof a compound of the formula VIII according to claim 17, or a saltthereof.
 61. (canceled)
 62. A method according to claim 58 comprisingthe steps of the manufacture of a compound of the formula VIII accordingto claim 17, or a salt thereof.
 63. (canceled)
 64. A method according toclaim 58 comprising the steps of the manufacture of a compound of theformula VIII according to claim 17, or a compound of the formula VIII′according to claim 25, or a salt of these, the manufacture of a compoundof the formula IX according to claim 30, or a compound of the formulaIX′ according to claim 46, or a salt of these.
 65. A method according toclaim 63 comprising the steps of the manufacture of a compound of theformula X according to claim 31, or a compound of the formula X′according to claim 33, or a salt of these, and/or the manufacture of acompound of the formula IX according to claim 35, or a compound of theformula IX′ according to claim 46, or a salt of these.
 66. A methodaccording to claim 48 comprising the steps of the manufacture of acompound of the formula X according to claim 31, or a salt thereof,and/or the manufacture of a compound of the formula XI according toclaim 36, or a salt thereof, and the manufacture of a compound of theformula IX according to claim 37, or a salt thereof.
 67. A method forpreparing a compound of formula (XIV)

wherein R³ and R⁴ are as defined for a compound of formula (II), R¹ andR² are as defined for a compound of formula (VIII), or a salt thereof,comprising one or more of the following steps either individually or inany combination: the manufacture of a compound of the formula Xaccording to claim 32, or a salt thereof, and the manufacture of acompound of the formula IX according to claim 39, or a salt thereof. 68.A method according to claim 41 comprising the steps of the manufactureof a compound of the formula X according to claim 32, or a salt thereof.